Assessment of the arachidonic acid content in foods commonly consumed in the American diet

Arachidonic acid (AA) is an extremely important fatty acid involved in cell regulation. When provided in the diet, it is cogently incorporated in membrane phospholipids and enhances eicosanoid biosynthesis in vivo and in vitro; however, controversy exists as to the levels of AA in food and in the diet. This study determined the amount of AA in cooked and raw portions of beef (rib eye), chicken (breast and thigh), eggs, pork (loin), turkey (breast), and tuna; it compared these results to values published in Agriculture Handbook No. 8 (HB-8). The cooked portions were prepared as described in HB-8. With the exception of chicken thigh and tuna, the levels of AA (w/w) in the selected foods analyzed were significantly higher, in general, than those values published in HB-8. The greatest differences were observed in beef (raw and cooked), turkey breast (raw and cooked), and pork (cooked) where AA levels were twice that of the values in HB-8. In contrast, the AA and n-3 fatty acid contents in tuna were almost half the HB-8 values. The present data indicate that HB-8 tends to underreport the amounts of AA in a number of foods commonly consumed in the American diet, and new initiatives should be considered to validate and update the current database for fatty acid composition of foods.     

Simultaneous liquid–liquid demixing and crystallization and its effect on the spherulite growth in poly(ethylene terephthalate)/poly(ether imide) blends

Poly(ethylene terephthalate) (PET)/poly(ether imide) (PEI) blends were miscible in the melt, but exhibited simultaneous liquid–liquid phase separation and crystallization over a wide range of temperature and composition. The interplay between these two processes is expected to dominate the morphological formation in the blends. In this study, the phase diagram of PET/PEI blend was determined to evaluate the envelop within which liquid–liquid phase separation was operative with crystallization. A UCST phase diagram below 240°C was identified for this system. The effect of liquid–liquid phase separation on the growth of PET spherulites was studied by small-angle light scattering (SALS). Nonlinear spherulite growths were observed for the blends at higher crystallization temperatures of 210°C and 220°C, while the growths were basically linear below 210°C. The nonlinear growth behaviour was discussed based on the competition between spherulite growth and spinodal decomposition.     

Kinetics of copper and high Pb/high Sn bilayered Pb-Sn solder interactions

Use of bilayered Pb-Sn solders consisting of high Sn and high Pb solder compositions is an option for joining chips to organic substrates at lower temperatures in which the high Sn solder is deposited onto Cu pads on the substrates. In this work interactions between the two-layered solder and copper pads during the reflow operation have been studied for both flip chip and Ball Grid Array (BGA) applications. It has been observed that Sn from the high Sn solder migrates faster at the edges along the surface of the high Pb solder than at the interior, resulting in a non-uniform Sn concentration along the Cu-solder interface. The thickness of the intermetallic compound formed due to the interaction of Cu and Sn has also been found to be non-uniform along the solder-Cu interface. This has been attributed to the variation in the Sn concentration of the solder adjacent to the Cu pads at different positions. The intermetallic compound growth rate has been explained using a model based on Sn diffusion into copper.     

Shape-optimized electrooptic beam scanners: analysis, design, andsimulation

This paper presents the analysis of a general nonrectangular electrooptic (EO) scanner and compare its performance to a rectangular device. Since the scanning sensitivity of an EO scanner is inversely proportional to its width, high sensitivity requires the device contour to be close to the ray trajectory of a beam propagating through the device. Accordingly, a shaped-optimized scanner is designed so that the beam trajectory at maximum deflection is parallel to the device contour. A beam propagation method (BPM) simulation shows the performance agrees well with the analysis     

Electromagnetic scattering interaction between a dielectriccylinder and a slightly rough surface

An electromagnetic scattering solution for the interaction between a dielectric cylinder and a slightly rough surface is presented in this paper. Taking the advantage of a newly developed technique that utilizes the reciprocity theorem, the difficulty in formulating the secondary scattered fields from the composite target reduces to the evaluation of integrals involving the scattered fields from the cylinder and polarization currents of the rough surface induced by a plane wave. Basically, only the current distribution of isolated scatterers are needed to evaluate the interaction in the far-field region. The scattered field from the cylinder is evaluated in the near-field region using a stationary phase approximation along the cylinder axis. Also, the expressions for the polarization current induced within the top rough layer of the rough surface derived from the iterative solution of an integral equation are employed in this paper. A sensitivity analysis is performed for determining the dependency of the scattering interaction on the target parameters such as surface root mean square (RMS) height, dielectric constant, cylinder diameter, and length. It is shown that for nearly vertical cylinders, which is of interest for modeling of vegetation, the cross-polarized backscatter is mainly dominated by the scattering interaction between the cylinder and the rough surface. The accuracy of the theoretical formulation is verified by conducting polarimetric backscatter measurements from a lossy dielectric cylinder above a slightly rough surface. Excellent agreement between the theoretical prediction and experimental results is obtained     

Elevated Monocytic Interleukin-8 Expression under Intermittent Hypoxia Condition and in Obstructive Sleep Apnea Patients

Obstructive sleep apnea (OSA) is a disease with great cardiovascular risk. Interleukin-8 (IL-8), an important chemokine for monocyte chemotactic migration, was studied under intermittent hypoxia condition and in OSA patients. Monocytic THP-1 cells were used to investigate the effect of intermittent hypoxia on the regulation of IL-8 by an intermittent hypoxic culture system. The secreted protein and mRNA levels were studied by means of enzyme-linked immunosorbent assay and RT/real-time PCR. The chemotactic migration of monocytes toward a conditioned medium containing IL-8 was performed by means of the transwell filter migration assay. Peripheral venous blood was collected from 31 adult OSA patients and RNA was extracted from the monocytes for the analysis of IL-8 expression. The result revealed that intermittent hypoxia enhanced the monocytic THP-1 cells to actively express IL-8 at both the secreted protein and mRNA levels, which subsequently increased the migration ability of monocytes toward IL-8. The ERK, PI3K and PKC pathways were demonstrated to contribute to the activation of IL-8 expression by intermittent hypoxia. In addition, increased monocytic IL-8 expression was found in OSA patients, with disease severity dependence and diurnal changes. This study concluded the monocytic IL-8 gene expression can be activated by intermittent hypoxia and increased in OSA patients.     

AR-12 Has a Bactericidal Activity and a Synergistic Effect with Gentamicin against Group A Streptococcus

Streptococcus pyogenes (group A Streptococcus (GAS) is an important human pathogen that can cause severe invasive infection, such as necrotizing fasciitis and streptococcal toxic shock syndrome. The mortality rate of streptococcal toxic shock syndrome ranges from 20% to 50% in spite of antibiotics administration. AR-12, a pyrazole derivative, has been reported to inhibit the infection of viruses, intracellular bacteria, and fungi. In this report, we evaluated the bactericidal activities and mechanisms of AR-12 on GAS infection. Our in vitro results showed that AR-12 dose-dependently reduced the GAS growth, and 2.5 μg/mL of AR-12 significantly killed GAS within 2 h. AR-12 caused a remarkable reduction in nucleic acid and protein content of GAS. The expression of heat shock protein DnaK and streptococcal exotoxins was also inhibited by AR-12. Surveys of the GAS architecture by scanning electron microscopy revealed that AR-12-treated GAS displayed incomplete septa and micro-spherical structures protruding out of cell walls. Moreover, the combination of AR-12 and gentamicin had a synergistic antibacterial activity against GAS replication for both in vitro and in vivo infection. Taken together, these novel findings obtained in this study may provide a new therapeutic strategy for invasive GAS infection.     

Development of an in-line viscometer in an extrusion molding process

In this work, an in-line viscometer to measure the viscosity of polymer melts under extrusion molding processes was developed. The in-line viscometer contains a stress sensor and a shear rate sensor which were installed between the screw and the die of an extruder. In this way, the flow line after the screw cannot be changed, unlike the present in-line capillary rheometer which can change the diameter of the pipe of the flow line and hence influence the throughput. All data acquisition is done by a computer such that the melt viscosity can be calculated automatically. The shear-thinning behavior of a low-density polyethylene (LDPE) under three different temperatures is presented in all experiments. It is concluded that the melt viscosity can be effectively monitored. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 919–924, 1997     

Kinetic approach for epoxy resins cured with diaminodiphenyl sulfone under non‐isothermal conditions

The curing reactions of epoxy resin basing on diglycidyl ether bisphenol A (DGEBA) with 4,4′‐diaminodiphenyl sulfone (DDS) were investigated with a differential scanning calorimeter and gel permeation chromatography. Based on the generating function method and the Monte Carlo simulation procedure, kinetic models for both isothermal and nonisothermal curing conditions were proposed. The apparent activation energy of curing reactions was found to be 14.9 Kcal/mol by the thermal analysis. According to our kinetic models, gel points, the profiles of epoxy conversion, and the molecular weights of polymers were calculated. Good agreement is obtained between the model predictions and experimental data. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 721–728, 1999     

Modification of Nylon 6 by phenol‐containing polymers

A crystalline polymer, Nylon 6, was selectively blended with various amorphous polymers containing phenolic moieties. It was found that moisture absorption by the amide group in Nylon 6 could effectively be reduced by blending with p‐Cl‐novolac at ratios as low as 2 phr (part per hundred resin). Blends of Nylon 6 with vinylphenol homopolymer and its copolymer with styrene also showed reduced moisture uptakes, but the effect was less dramatic than that of the p‐Cl‐novolac blend at all blend ratios. Novolac content in excess of 5 phr shows little additional advantage in moisture reduction. Thermal transitions of blends of Nylon 6 with poly(vinyl phenol), its copolymer, and p‐Cl‐novolac were also investigated. At a blend ratio of 5 phr, p‐Cl‐novolac caused a larger increase in glass transition temperature than the other two blends. The melting temperatures of the blends were little influenced by low levels of the amorphous polymer incorporation, but broader melting endotherms in the differential scanning calorimetry scans were observed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 295–300, 1999