An inverse method for imaging the local elasticity of atherosclerotic coronary plaques

The rupture of thin-cap fibroatheroma (TCFA) plaques is a major cause of acute coronary events. A TCFA has a trombogenic soft lipid core, shielded from the blood stream by a thin, possibly inflamed, stiff cap. The majority of atherosclerotic plaques resemble a TCFA in terms of overall structural composition, but have a more complex, heterogeneous morphology. An assessment of the material distribution is vital for quantifying the plaque's mechanical stability and for determining the effect of plaque-stabilizing pharmaceutical agents. We describe a new automated inverse elasticity method, intravascular ultrasound (IVUS) modulography, which is capable of reconstructing a heterogeneous Young's modulus distribution. The elastogram (i.e., spatial strain distribution) of the plaque is the input for the method, and is measured using the clinically available technique, IVUS elastography. Our method incorporates a novel divide-and-conquer strategy, allowing the reconstruction of TCFAs as well as heterogeneous plaques with localized regions of soft, weakened tissue. The method was applied to ex vivo elastograms, which were simulated from the cross sections of postmortem human coronary plaques. To demonstrate the clinical feasibility of the method, measured elastograms from human atherosclerotic coronary arteries were analyzed. One elastogram was measured in vitro; the other, in vivo. The method approximated the true Young's modulus distribution of all simulated plaques, while the in vitro reconstruction was in agreement with histology. In conclusion, the IVUS modulography in combination with the IVUS elastography has strong potential to become an all-encompassing modality for detecting plaques, for assessing the information related to their rupture-proneness, and for imaging their heterogeneous elastic material composition.     

Yield and flour quality of spring wheat as affected by soil tillage and animal manure

BACKGROUND: Yield and quality of organic bread wheat may be improved by adjusting tillage and type of manure. We tested two different tillage strategies (rotovation plus ploughing or ploughing only) before sowing spring wheat (Triticum aestivum L.) on a coarse loamy sand. The tillage strategies were combined with four nitrogen (N) rates of animal manure supplied in either slurry or liquid manure. RESULTS: Rotovation before ploughing had only a negligible influence on soil inorganic N content in the spring and on wheat biomass development. Liquid manure gave a higher protein and gluten content than slurry, probably due to its higher proportion of inorganic N. At low N rates, gluten from wheat supplied with slurry was softer than from wheat given liquid manure and responded differently to baking tests than expected from their gluten and protein content. At higher N rates, loaf volume corresponded well with the gluten and protein content. CONCLUSION: Soil tillage intensity did not have a major influence on soil N mineralisation patterns and manure N availability. Except at low N rates, the response of wheat flour to different types of animal manure is mainly determined by the amount of inorganic N supplied. Copyright © 2008 Society of Chemical Industry     

Characterization of the packing of aggregate in concrete by a discrete element approach

Aggregate roughly takes up three-quarters of the volume of concrete, so it plays an important role in the properties of concrete. A particle packing phenomenon exists in a wide range of fields as well as in concrete technology. A spherical grain shape is generally adopted in conventional discrete element simulation (DES) systems, despite imposing serious limitations. In this paper, a flexible simulation strategy is presented for the simulation of arbitrary-shaped aggregate grains used in concrete technology. This simulation approach is also incorporated in a concurrent algorithm-based DES system. Furthermore, a method has been developed for the assessment of properties pertaining to arbitrary shaped particles, such as mass, centre of mass, and moment of inertia. Some trials of particle packing with different shapes are also revealed and discussed in this paper.     

Synthesis of ultrathin rhenium disulfide nanoribbons using nano test tubes

The synthesis of ultrathin rhenium disulfide(ReS₂)nanoribbons within single-walled carbon nanotubes(SWNTs)has been established.Dirhenium decacarbonyl complex is encapsulated into the SWNTs to provide a source of confined rhenium atoms,which readily react with iodine to form discrete nm-sized clusters of rhenium iodide[Re₆l₁₄]^2- embedded in the nanotubes.The final step of the synthesis is accomplished by admitting hydrogen sulfide gas into nano test tubes,yielding twisted nanoribbons of rhenium disulfide encapsulated in carbon nanotubes,ReS₂@SWNTs.The width,structure,and composition of rhenium disulfide nanoribbons are strictly controlled by the extreme confinement of the host-SWNT.A holistic analytical approach combining complementary imaging and analysis methods is used at each synthetic step to elucidate the structure and composition of the guest material and reveal the role of the SWNT contributing towards the electronic interactions with encapsulated inorganic structures.As ReS₂ nanoribbons are expected to retain the electronic properties of the bulk material,such as direct bandgap,the low dimensional form of this material can be of interest for use in nanoscale electronic devices.     

Oxidation of Various Kraft Lignins with a Bacterial Laccase Enzyme

Modification of kraft lignin (KL), traditionally uses harsh and energy-demanding physical and chemical processes. In this study, the potential of the bacterial laccase CotA (spore coating protein A) for oxidation of KL under mild conditions was assessed. Thereby, the efficiency of CotA to oxidize both softwood and hardwood KL of varying purity at alkaline conditions was examined. For the respective type of wood, the highest oxidation activity by CotA was determined for the medium ash content softwood KL (MA_S) and the medium ash content hardwood KL (MA_H), respectively. By an up to 95% decrease in fluorescence and up to 65% in phenol content coupling of the structural lignin units was indicated. These results correlated with an increase in viscosity and molecular weight, which increased nearly 2 and 20-fold for MA_H and about 1.3 and 6.0-fold for MA_S, respectively. Thus, this study confirms that the CotA laccase can oxidize a variety of KL at alkaline conditions, while the origin and purity of KL were found to have a major impact on the efficiency of oxidation. Under the herein tested conditions, it was observed that the MA_H KL showed the highest susceptibility to CotA oxidation when compared to the other hardwood KLs and the softwood KLs. Therefore, this could be a viable method to produce sustainable resins and adhesives.     

寇司德热均匀辊热轧机

寇司德公司新设计的热均匀辊热轧机既可用于传统的非织造布生产线,又适用于现代高速生产线,其技术核心在于有挠度补偿的均匀辊,可在整个产品幅宽上形成完全一致的线压力。     

Phasenwechselmaterial in Kugelkapseln für thermische Hybridspeicher

Heat and cold storage systems of buildings are based on different concepts of heat transfer. In thermal hybrid storage systems, the phase change material (PCM) is macroencapsulated in PCM objects which are positioned in the storage tank and around which the heat transfer fluid flows. The experimental investigations are dedicated to the loading and unloading properties of the PCMs macroencapsulated in spheres. It is shown that the specific heat transfer performance of a hybrid storage tank is directly dependent on the size of the spheres as well as on the specific thermal conductivity of the PCM.     

Kinetics and Mechanisms of Dolime Dissolution in Steelmaking Slag

Metallurgical and Materials Transactions B - The kinetics of dolime dissolution containing 20 and 50 pct of magnesium oxide in steelmaking slags has been studied in a high-temperature...