How disorder can diminish avalanche risks: effect of size distribution

We study the behavior of disk assemblies with a variable disorder distribution. The packing is first consolidated and then continuously tilted very slowly. The amount of displaced disks for each tilted angle is recorded. Large displacements of the disks can occur due to some local or global mechanical instabilities. The definition of neighboring disks is based on radical (extension of Voronoï) tessellation rules to decompose, in a unique and perfectly defined manner, the two-dimensional space for polydisperse disks. In this way, by comparing the characteristics of stability for one disk to the neighboring ones for local ordered cluster, we can predict the global amount of displaced disks. Some tilting cycles have been performed to check the correlation between the instability of the packing structure (collective displacements) with micro and macro order parameters.     

Impact of apolipoprotein E polymorphism on lipoproteins and risk of myocardial infarction. The ECTIM Study

Human apolipoprotein (apo) E, a polymorphic protein with three common alleles, epsilon 2, epsilon 3, and epsilon 4, plays an important role in lipoprotein metabolism. This article describes the association of this polymorphism with lipids, apolipoproteins, and lipoproteins with a particular regard to lipoprotein particles, as defined by their apolipoprotein content, as well as the risk of myocardial infarction in a multicenter population-based case-control study (ECTIM study). In the ECTIM study, 574 male patients aged 25 to 64 were examined 3 to 9 months after myocardial infarction in four regions participating in the World Health Organization MONICA project: Belfast (Northern Ireland) and Lille, Strasbourg, and Toulouse (France). Control subjects (n = 722) were randomly selected from the regional populations. The distribution of apoE phenotypes was significantly different across the four control samples (P = .04), with a higher frequency of the epsilon 4 allele in Belfast (14.3%) than in Toulouse (8.2%). The association of apoE polymorphism with biological measurements was studied in the control groups (n = 640) after men with coronary heart disease or those taking hypolipidemic drugs were omitted, with the apoE3/3 phenotype as a reference after adjustment for concomitant factors. Individuals carrying the epsilon 2 allele had lower levels of plasma cholesterol, low-density lipoprotein cholesterol (LDL-C), and apoB and higher levels of triglycerides, very-low-density lipoprotein cholesterol (VLDL-C), apoC-III, apoE, lipoprotein (Lp) C-III:B, and Lp E:B. However, the effect of the epsilon 2 allele on triglyceride, VLDL-C, apoE, and Lp E:B parameters was heterogeneous across the populations.(ABSTRACT TRUNCATED AT 250 WORDS)     

Patterns of Fos-like immunoreactivity in the brains of parent ring doves (Streptopelia risoria) given tactile and nontactile exposure to their young.

Neuronal activation was examined by fos immunohistochemistry in ring doves (Streptopelia risoria) reunited with their young after overnight separation. In an initial study, squab-exposed parents showed more fos immunoreactivity (ir) in the preoptic area (POA) and lateral hypothalamus (LH) than squab-deprived parents. In a 2nd study, parents allowed free access to young and those separated from young by a wire mesh partition showed more fos-ir in the POA, LH, and lateral septum than box-exposed controls. Contact with young also increased fos-ir in the medial preoptic nucleus and bed nucleus of the stria terminalis, but noncontact exposure did not. Conversely, nontactile squab exposure stimulated more fos-ir in the POA than did free access to young, which suggests POA involvement in appetitive aspects of parenting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Altered mRNA and Protein Expression of Monocarboxylate Transporter MCT1 in the Cerebral Cortex and Cerebellum of Prion Protein Knockout Mice

The effect of a cellular prion protein (PrP^c) deficiency on neuroenergetics was primarily analyzed via surveying the expression of genes specifically involved in lactate/pyruvate metabolism, such as monocarboxylate transporters (MCT1, MCT2, MCT4). The aim of the present study was to elucidate a potential involvement of PrP^c in the regulation of energy metabolism in different brain regions. By using quantitative real-time polymerase chain reaction (qRT-PCR), we observed a marked reduction in MCT1 mRNA expression in the cortex of symptomatic Zürich I Prnp^−/− mice, as compared to their wild-type (WT) counterparts. MCT1 downregulation in the cortex was accompanied with significantly decreased expression of the MCT1 functional interplayer, the Na⁺/K⁺ ATPase α2 subunit. Conversely, the MCT1 mRNA level was significantly raised in the cerebellum of Prnp^−/− vs. WT control group, without a substantial change in the Na⁺/K⁺ ATPase α2 subunit expression. To validate the observed mRNA findings, we confirmed the observed change in MCT1 mRNA expression level in the cortex at the protein level. MCT4, highly expressed in tissues that rely on glycolysis as an energy source, exhibited a significant reduction in the hippocampus of Prnp^−/− vs. WT mice. The present study demonstrates that a lack of PrP^c leads to altered MCT1 and MCT4 mRNA/protein expression in different brain regions of Prnp^−/− vs. WT mice. Our findings provide evidence that PrP^c might affect the monocarboxylate intercellular transport, which needs to be confirmed in further studies.     

Global insight into microwave stoneware firing: Macro and microstructural changes

Industrial competition and environmental concerns lead to the exploration of alternative and energy-efficient technologies for ceramic materials processing. The main objective of this work was to present microwave heating as a viable option for stoneware processing. Stoneware functional properties are presented and discussed, with emphasis on impact strength, water absorption, porosity, and color. Microstructure analyses show that microwave- and gas-fired samples have higher densifications than electrically fired samples. A relevant finding for processing conditions is that microwave firing requires temperatures approximately 100°C lower than those required by conventional firing. Microwave-fired samples’ rupture energies are approximately twice (0.57 ± 0.06 (J)) those of the reference samples (0.26 ± 0.03 (J)), and their water absorptions are approximately one-half (1.5% at 1170°C and 0.8% at 1190°C) of those of the reference samples (2.0%), whereas the water absorption of electrically fired samples at 1180°C has been estimated to be 7.5%. Color analysis also evidences a shift to lower microwave firing temperatures, what is attributed to the enhanced transformations promoted by microwave heating when comparing with the transformations promoted by conventional (gas or electric) heating.     

A review of the current status of small-scale seawater reverse osmosis desalination

The current status of small-scale desalination (produced water capacity 100 m³/day or less) is reviewed to provide an overview of the market segment. The use of energy-recovery devices in this market segment is also reviewed. We find that the Middle East accounts for the largest market share worldwide at present, and reverse osmosis is overwhelmingly dominant among the desalination technologies adopted. Implementation of energy-recovery devices at small scale is rare, which leads to relatively high energy consumption for small-scale seawater reverse osmosis desalination systems.     

Two-dimensional correlation relaxometry studies of cement pastes performed using a new one-sided NMR magnet

We present preliminary results of the first NMR T₁-T₂ two-dimensional relaxation correlation experiments performed using a one-sided NMR system in cement based materials. Two-dimensional correlation relaxometry has itself only recently been demonstrated in cement paste where it proved to be a particularly sensitive probe of pore-water dynamics providing direct information on exchange of water between the gel and capillary pore networks. Further to this we have observed differences in the structural development of a selection of cement pastes throughout the early stages of hydration and verified the theoretical frequency dependence of the ratio T₁ / T₂. When coupled with instrumentation developments in one-sided NMR magnets the way is opened to detailed, spatially resolved studies of the development of hydration and porosity in the surface layers (top 50 mm) of cementitious materials. A new magnet, suitable for such applications, is discussed.     

Selectivity of Supercritical CO<Subscript>2 </Subscript>in the Fractionation of Hake Liver Oil Ethyl Esters

The solubility of different ethyl esters derivatized from hake liver oil in supercritical carbon dioxide was studied. A selectivity factor was used to determine optimal conditions to fractionate the ethyl ester mixture. A strong influence of solvent pressure and temperature was observed within 8.63–18.04 MPa and 40–70 °C. The lowest total solubility of the ethyl ester mixture was obtained when using supercritical carbon dioxide at the lowest density (the lowest pressure and the highest temperatures value tested). The highest discrimination against long-chain polyunsaturated fatty acids (e.g. EPA and DHA) was also obtained at these above conditions. Conversely, higher solubility and lower selectivity were obtained when solvent density increased. Considering this inverse correlation between selectivity and solubility, a single-step batch-fractionation process was designed to increase the 22:6 ethyl ester content from an initial value of 17.5% in the starting material to 55% in the final extract.