Surface‐pegylated chitin whiskers as an effective additive to enhance the mechanical properties of recycled ABS

The recyclability of materials is a key issue related to the use of polymers in the automotive and electronic industries, among others. The multiple thermal and mechanical operations used in recycling can cause severe damage to the molecular architecture and microstructure of polymers that frequently leads to a reduction in their mechanical properties, which restricts their recyclability. In this work, nanocomponents (whiskers) derived from chitin were surface‐modified by grafting different molar masses of methoxylated poly(ethylene glycol) (mPEG). The modified chitin whiskers were then incorporated into reprocessed ABS (acrylonitrile–butadiene–styrene) to yield nanocomposites with 0.5% (mass/mass) whiskers. The obtained whiskers and nanocomposites were investigated using techniques such as transmission electron microscopy, atomic force microscopy, scanning electron microscopy, infrared spectroscopy, and thermogravimetric analysis. The properties of the nanocomposites were also investigated using tensile tests and dynamic mechanical tests. The results show that the surface‐modified chitin whiskers with high molar mass mPEG grafts increased the strength, elongation at break, and stiffness of the reprocessed ABS over virgin and reprocessed ABS and reprocessed ABS nanocomposites with unmodified whiskers. This indicates that the use of surface‐modified chitin whiskers can be valuable in improving the mechanical properties of recycled polymers and, consequently, enhancing their recyclability. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42463.     

Field performance evaluation of stone interlayer pavement in Louisiana

In this study, field performance of a stone interlayer pavement test section and cement-stabilised base test control section on LA-97 in Acadia Parish, Louisiana, was monitored during 20 years of service. In addition, the performance of other nine stone interlayer pavement sections in Louisiana constructed from 1999 to 2008 was monitored and evaluated. Field evaluations in this study included distress surveys on all 11 pavement sections, and non-destructive evaluation of pavement structure by the falling weight deflectometer and the dynamic deflection determination system test on nine of these sections. The field evaluation results indicated that the stone interlayer test section on LA-97 had a superior pavement performance to control section over the 20 years of service, and other nine stone interlayer pavement sections were in good pavement condition after 2.5–12 years of service.     

Human obesity is associated with a chronic elevation in brain 5-hydroxytryptamine turnover

The afferent signals that evoke changes in energy intake with regard to body weight regulation are presumed to arise partly from body stores, with the most likely candidate being adipose tissue depots. However, clinical investigation of the neuronal circuitry involved in the central nervous system's processing of such satiety signals remains largely unexplored. Using percutaneously placed catheters in either the right or left internal jugular veins, we were able to quantify the release of central nervous system monoamine and indoleamine neurotransmitters in 64 weight-stable male subjects with varying degrees of adiposity. Veno-arterial plasma concentration differences and internal jugular blood or plasma flow were used, according to the Fick Principle, to quantify the amount of neurotransmitter stemming from the brain. By combining this technique with a noradrenaline and adrenaline isotope dilution method for examining neuronal transmitter release, we were able to examine the association between central nervous system neurotransmitters and efferent sympathetic nervous outflow and adrenomedullary function in human obesity. We found that brain 5-hydroxytryptamine (serotonin) turnover is chronically elevated in proportion to adiposity and is increased postprandially to a similar degree in lean and obese individuals. There was no difference in the degree of sympathetic nervous activity or rate of adrenaline secretion in the subjects examined. It therefore seems that in human obesity, in the face of a chronic elevation in peripheral satiety signals, brain serotonergic processes are switched on accordingly, but the subsequent physiological response involving a reduction in food intake, increased thermogenesis and sympathetic activity is in some way impeded.     

Double-lumen aortic arch by persistence of fifth aortic arch: A new case associated with coarctation

Adrenodoxin reductase is an essential component of the mitochondrial monooxygenase systems that are involved in the synthesis of steroid hormones and related compounds. After removing by mutagenesis a secondary ribosome binding site and an mRNA loop formed between the gene and the vector, large amounts of the enzyme could be produced in Escherichia coli by coexpression with the HSP60-chaperone system. The purified protein was homogeneous enough for reproducible crystallization. The crystals diffracted X-rays isotropically beyond 1.7 A resolution permitting a structure analysis.     

Trypanosoma musculi: tracking parasites and circulating lymphoid cells in host mice

Hyperglycemia can cause vascular dysfunctions by multiple factors including hyperosmolarity, oxidant formation, and protein kinase C (PKC) activation. We have characterized the effect of hyperglycemia on p38 mitogen-activated protein (p38) kinase activation, which can be induced by oxidants, hyperosmolarity, and proinflammatory cytokines, leading to apoptosis, cell growth, and gene regulation. Glucose at 16.5 mM increased p38 kinase activity in a time-dependent manner compared with 5.5 mM in rat aortic smooth muscle cells (SMC). Mannitol activated p38 kinase only at or greater than 22 mM. High glucose levels and a PKC agonist activated p38 kinase, and a PKC inhibitor, GF109203X, prevented its activation. However, p38 kinase activation by mannitol or tumor necrosis factor-alpha was not inhibited by GF109203X. Changes in PKC isoform distribution after exposure to 16.5 mM glucose in SMC suggested that both PKC-beta2 and PKC-delta isoforms were increased. Activities of p38 kinase in PKC-delta- but not PKC-beta1-overexpressed SMC were increased compared with control cells. Activation of p38 kinase was also observed and characterized in various vascular cells in culture and aorta from diabetic rats. Thus, moderate hyperglycemia can activate p38 kinase by a PKC-delta isoform-dependent pathway, but glucose at extremely elevated levels can also activate p38 kinase by hyperosmolarity via a PKC-independent pathway.     

Evaluation of the Residence Time of a Moving Fuel Bed on a Forward Acting Grate

The objective of this study is to identify numerical approaches and to employ them to evaluate the residence time of a moving bed on a forward acting grate. Obtaining residence times of fuel particles on a grate favours more reliable design of grate furnaces. The moving bed was represented by spherical particles, whereby a varying size accounts for the variety of particle geometries in a combustion chamber. In order to describe accurately the motion of a moving bed e.g. its particles, the discrete element method was applied. Thus, detailed data on all the particle’s paths and velocities are available. These data were used within two statistical approaches to estimate the residence time of a moving bed. One approach is based on a spatial averaging procedure, while the other relies on tracking the particle’s path. Both methods yielded satisfactory agreement with measurements, however, better predictions were obtained by tracking particles.Academic visitor to the Lithuanian Energy Institute     

Pleiotrophin and midkine, a family of mitogenic and angiogenic heparin-binding growth and differentiation factors

The lipid emulsions used in parenteral nutrition are constituted of particles rich in triacylglycerols (TAG) called artificial chylomicrons (200-500 nm in diameter; monolayer of phospholipids [PL] enveloping a TAG core) and PL-rich particles called liposomes (diameter inferior to 80 nm; bilayer of PL around an aqueous phase), which represent the excess emulsifier. Introduced into the circulation, the two populations of particles come into contact with circulating lipoproteins and cell membranes and experience the same overall fate: exchanges and transfers of lipids and apolipoproteins, enzymatic hydrolysis of TAG and PL, and internalization by different tissues. The relative importance of these different metabolic processes varies depending on the type of particle. The artificial chylomicrons undergo a hydrolysis of their TAG by lipoprotein lipase, with a release of fatty acids and formation of smaller particles of remnants, which are rapidly removed by the liver. In delivering fatty acids to the tissue, artificial chylomicrons fulfill an energy transport function similar to the natural chylomicrons. The liposomes hold little energy interest, and they also have deleterious effects when infused in excess. They inhibit the lipolysis of artificial chylomicrons and, by actively capturing endogenous cholesterol, they stimulate tissue cholesterogenesis and accumulate in the blood as lipoprotein-X, a long-lived abnormal lipoprotein. To limit as much as possible the metabolic perturbations due to the intravenous administration of exogenous PL, the emulsion has to be infused at a low rate, and should contain the minimal amount of excess PL.     

Sizing oxidation systems as heat and power recovery

There are large numbers of manufacturing processes that involve emissions of controlled chemical vapours also referred to as volatile organic compounds (VOC). The two most common processes used in industry to separate VOCs before they are emitted to the atmosphere are condensation and oxidation. Condensation requires a refrigeration system that would separate the VOC from the exhaust stream. Oxidation, sometimes known as afterburner or incineration, requires high thermal energy to combust the VOC. Both abatement technologies involve large capital costs. In the case of combusting the VOC, fuel is usually added to the air/VOC mixture for proper air/fuel ratio. The resulting high temperature gas from the energy intensive process is sometimes recovered as an offshoot of the VOC destruction process. Typically, oxidation systems are sized solely with elimination of VOC in mind; heat recovery from the system is opted for as a secondary opportunity, usually at a later stage. This paper demonstrates that combining the oxidation process with combined heat and power (CHP) to address the total site energy requirement could have significant energy saving and economic benefits to sizing the oxidation for VOC destruction marking heat recovery as a spin‐off. Copyright © 2005 John Wiley & Sons, Ltd.