Temperature excursions during the transient behaviour of high temperature catalytic combustion monoliths

Spatio-temporal temperature profiles experimentally observed during the operation of a structured perovskite-based catalytic monolith for the combustion of methane were simulated by means of a transient heterogeneous one-dimensional model which accounts for heat losses to the surroundings and thermal conductivity inside the monolith substrate. In fact it is shown that such thermal phenomena are essential to correctly reproduce the slow warm-up transients and the wrong-way behaviour observed in a low conductivity ceramic monolith. Model simulations reveal that at higher values of solid conductivity the catalyst does not exhibit hot spot both in time and space, but needs higher inlet gas temperatures to reach complete methane conversion. Bifurcation analysis of the catalytic monolith reactor model were carried out to study steady-state multiplicity. We show that the origin of multiplicity is purely thermal as it is mainly ruled by the heat transfer through the external surface.     

Nutritional and stability evaluation during storage of blends extruded with sorghum

Binary sorghum:soy (70:30) and ternary sorghum:corn:soy (30:40:30) blends using high and low tannin content dehulled sorghum were extruded. The effectiveness of heat treatment was determined by protein dispersion index (PDI) and ureasic activity (delta PH), indicating that proteins were denatured and antinutritional factors reduced. The nutritional evaluation supported the fact that samples were adequately treated, giving ternary blends true digestibility (TD) and biological values (BV) similar to milk casein. Blend stabilities, expressed as peroxide index (PI), revealed a low lipid oxidation rate during the first seven months, and were acceptable up to a year of storage. Extrudates with incorporated sorghum cover protein and energy demands of the growing infant, and provide a high nutritional value and long-life product.     

Control of endothelial leukocyte adhesion molecules by fatty acids

Dietary balance of long-chain fatty acids (FA) may influence human susceptibility to pathological processes which involve the interaction of leukocytes with vascular endothelium, such as atherogenesis and inflammation. Such interaction is largely mediated by thede novo or increased expression of endothelial leukocyte adhesion molecules on vascular endothelial cells, able to tether and stably bind leukocytes onto the vessel wall, and by the production of leukocyte chemoattractants. Endothelial cells do not normally support high levels of leukocyte adhesion. They do so, however, when exposed to a number of stimuli, such as oxidized low density lipoprotein bacterial lipopolysaccharides, and inflammatory cytokines, which induce phenotypic changes generally referred to as “endothelial activation.” We compared various FA in their ability to modulate endothelial activation by cytokines. FA included linoleic, arachidonic, oleic, eicosapentaenoic and, docosahexaenoic acid (DHA) as representatives of the n-6, n-3 polyunsaturated FA and of the monounsaturated FA. The n-3 FA DHA, and, to a lesser extent, oleate, at nutritionally compatible concentrations, were able to reduce endothelial expression of Vascular Cell and Adhesion Molecule-1 (VCAM-1). In further studies, DHA dose- and time-dependently reduced also the expression of E-selectin, Intercellular Adhesion Molecule-1, interleukin (IL)-6 and IL-8, in response to IL-1, IL-4, tumornecrosis factor, or bacterial endotoxin. The magnitude of this effect paralleled its incorporation into cellular phospholipids. Also, coordinate with reduced surface adhesion molecule expression, DHA reduced the adhesion of human monocytes and of monocytic U937 cells to cytokine-stimulated endothelial cells. These effects were accompanied by a quantitatively consistent reduction in VCAM-1 mRNA, indicating a pretranslational control of adhesion molecule gene expression. These novel properties of FA as modulators of endothelial activation may help to explain the influence of dietary FA intake on atherogenesis and inflammation. A substantial part of the data presented in this paper has been previously published [Arterioscler. Thromb. 14, 1829–1836 (1994)], and are here reported with permission of the American Heart Association.     

Mesothelioma and Colorectal Cancer: Report of Four Cases with Synchronous and Metachronous Presentation

There is evidence that asbestos could play a role in the carcinogenesis of digestive cancers. The presence of asbestos fibres in histological samples from gastric, biliary, colon cancers has been reported, but the mechanism is still controversial. It has been hypothesised that asbestos reaches these sites, especially through contaminated water; however, some experimental studies have shown that the inhaled fibres are mobile, so they can migrate to many organs, directly or via blood and lymph flow. We report four unusual cases of colorectal cancers in patients with a long history of asbestos exposure who also developed synchronous or metachronous mesothelioma. We evaluated the roles of BRCA associated protein-1 (BAP1) and cyclin-dependent kinase inhibitor 2A (CDKN2A) in colon cancer and mesothelioma to support the hypothesis that BAP-1 and CDKN2A are tumour suppressor genes involved in disease progression, recurrence, or death in both digestive cancers and mesothelioma. Potentially, these markers may be used as predictors of worse prognosis, but we also stress the importance of clinical surveillance of exposed patients because asbestos could induce cancer in any organ.     

Sex Hormones and Their Effects on Ocular Disorders and Pathophysiology: Current Aspects and Our Experience

Sex hormones are molecules produced by the gonads and to a small extent by the adrenal gland, which not only determine the primary and secondary sexual characteristics of an individual, differentiating man from woman, but also participate in the functioning of the various systems of the body. The evidence that many eye diseases differ in terms of prevalence between men and women has allowed us, in recent years, to carry out several studies that have investigated the association between sex hormones and the pathophysiology of eye tissues. Specific receptors for sex hormones have been found on the lacrimal and meibomian glands, conjunctiva, cornea, lens, retina, and choroid. This work summarizes the current knowledge on the role that sex hormones play in the pathogenesis of the most common ocular disorders and indicates our clinical experience in these situations. The aim is to stimulate an interdisciplinary approach between endocrinology, neurology, molecular biology, and ophthalmology to improve the management of these diseases and to lay the foundations for new therapeutic strategies.     

Biochemical and molecular characterization of hereditary myeloperoxidase deficiency

Hereditary myeloperoxidase (MPO) deficiency is a neutrophil disorder characterized by the lack of peroxidase activity. Cytochemical, biochemical, spectroscopic, immunocytochemical, and genetic studies were carried out on a 5-year-old MPO-deficient subject and on her parents. The father was also MPO-deficient, whereas the mother had 24% of normal MPO activity. Although the typical absorption spectrum of MPO was absent in both the father and daughter, the father's neutrophils, and not those of the daughter, contained material antigenically related to MPO. In the MPO gene of the father, two mutations were found, each located in a different allele: a T --> C transition, causing the nonconservative replacement M251T and a 14-base deletion within exon 9. The M251T substitution occurred in the carboxy-terminal region of the light chain that is included in the heme pocket. The daughter inherited the 14-base deletion from her father. The study of the MPO mRNAs present in liquid cultures of granulocyte precursors surprisingly showed that the same genetic defect, ie, the 14-base deletion, seemed to exhibit different mRNA phenotypes in the father and the daughter. In fact, mRNA derived from the 14-base-deleted allele was not found in the father and an aberrantly spliced MPO mRNA with a 77-base deletion of exon 9, which includes the 14-base deletion and leads to the generation of a premature stop codon, was found in the daughter. The possibility that Delta77 mRNA could derive from other mutations linked to the Delta14 allele was dismissed because no sequence differences were found in the region (exons and exon-intron junctions). Our data indicate that the alteration of the mRNA context caused by the 14-base deletion provide a basis for the 77-base deletion in the mRNA processing. Since the granulocyte precursors from the liquid cultures of the father were more differentiated than those from the daughter, the observed different behavior of the 14-base-deleted allele in the father and daughter may be the result of a differentiation-stage dependent control of altered spliced mRNA, which may be tolerated during the early stages of differentiation but degraded at later stages. In the liquid cultures of the daughter's cells, in addition to the mRNA with the 77-base deletion, a mRNA with the wild type sequence was also found. This mRNA was inherited from the mother, since no mutations were found in her MPO cDNA and MPO gene. The MPO defect might be caused by a regulatory mutation that induces the MPO gene switch off at an early stage of granulocyte differentiation.     

Extinction and retention of a classically conditioned flexor nerve response in acute spinal cat.

Conditioned adult male and female cats by pairing a mild electrical stimulus to the superficial peroneal sensory nerve (CS) with a stronger electrical stimulus to the ankle skin (UCS) of the same leg. Subsequent extinction was produced by presenting CS-alone trials. In Exp I (42 Ss), Ss given massed extinction trials showed response decrements to base levels, but Ss that received distributed extinction trials showed no decrements. In Exp II, .5-, 1-, 2-, 3-, or 4-hr intervals between acquisition and extinction produced no significant differences in the extinction data. In Exp III (20 Ss), Ss received extinction trials immediately or 30 min after acquisition trials, followed by 20 additional extinction trials 30 min later. Data indicated significant acquisition and extinction in the 10- and 20-acquisition trial groups. As in Exp II (35 Ss), varying the interval between acquisition and extinction did not produce any group differences in the extinction data. These results demonstrate that response increases produced by paired trials in the spinal preparation do not decay spontaneously over time and are not caused by sensitization effects. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Homogentisic Acid and Gentisic Acid Biosynthesized Pyomelanin Mimics: Structural Characterization and Antioxidant Activity

Pyomelanin mimics from homogentisic acid (HGA) and gentisic acid (GA) were biosynthesized by the oxidative enzyme T. versicolor laccase at physiological pH to obtain water soluble melanins. The pigments show brown-black color, broad band visible light absorption, a persistent paramagnetism and high antioxidant activity. The EPR approach shows that at least two different radical species are present in both cases, contributing to the paramagnetism of the samples. This achievement can also shed light on the composition of the ochronotic pigment in the Alkaptonuria disease. On the other hand, these soluble pyomelanin mimics, sharing physico-chemical properties with eumelanin, can represent a suitable alternative to replace the insoluble melanin pigment in biotechnological applications.     

Decentralized Control for Residential Energy Management of a Smart Users' Microgrid with Renewable Energy Exchange

This paper presents a decentralized control strategy for the scheduling of electrical energy activities of a microgrid composed of smart homes connected to a distributor and exchanging renewable energy produced by individually owned distributed energy resources. The scheduling problem is stated and solved with the aim of reducing the overall energy supply from the grid, by allowing users to exchange the surplus renewable energy and by optimally planning users' controllable loads. We assume that each smart home can both buy/sell energy from/to the grid taking into account time-varying non-linear pricing signals. Simultaneously, smart homes cooperate and may buy/sell locally harvested renewable energy from/to other smart homes. The resulting optimization problem is formulated as a non-convex non-linear programming problem with a coupling of decision variables in the constraints. The proposed solution is based on a novel heuristic iterative decentralized scheme algorithm that suitably extends the Alternating Direction Method of Multipliers to a non-convex and decentralized setting. We discuss the conditions that guarantee the convergence of the presented algorithm. Finally, the application of the proposed technique to a case study under several scenarios shows its effectiveness.