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Process Leads (process + lead)
Selected AbstractsLeft Ventricular Non Compaction in ChildrenCONGENITAL HEART DISEASE, Issue 5 2010Sara H. Weisz MD ABSTRACT Left ventricular non compaction (LVNC) is a myocardial disease characterized by a hypertrabeculated myocardium. The hypertrabeculations in the left ventricular wall define deep recesses communicating with the left ventricular chamber where blood penetrates with increased risk of blood clots in the meshwork of the prominent trabeculations. The left ventricular apex and the free wall are particularly affected. During in utero ventriculogenesis, myocardial blood supply is initially linked to the presence of sinusoids, in which blood penetrates and diffuses nutriments and oxygen to myocardial cells. Progressively, with the development of the heart and the increase of cells demand of blood, coronary arteries system develops. This step is associated with myocardial modification that leads to compaction of hypertrabeculated myocardial net. Probably, the premature interruption of this process leads to ventricular noncompaction. Many studies have been conducted in adults with hypertrabeculated myocardium. To date, data regarding childhood LVNC are sparse. The aim of this review is to summarize the clinical and preclinical knowledge about LVNC in children. [source] Influences of the Process Chain on the Fatigue Behavior of Samples with Tension Screw Geometry,ADVANCED ENGINEERING MATERIALS, Issue 4 2010Marcus Klein To analyze the influence of the material batch, the structure of the manufacturing process chain, and the process parameters, four different material batches of the quenched and tempered steel SAE 4140 were used to manufacture samples with tension screw geometry. Five different, manufacturing process chains, consisting of the process steps heat treatment, turning, and grinding, were applied. After selected process steps, light and SEM micrographs as well as fatigue experiments were performed. The process itself as well as the process parameters influences the properties of the surface layers and the fatigue behavior in a characteristic manner. For example the variation of the feed rate and cutting speed in the hard-turning process leads to significantly different mechanical properties of the surface layers and residual stress states, which could be correlated with the fatigue behavior. The cyclic deformation behavior of the investigated components can be benchmarked equivalently with stress,strain hysteresis as well as high precision temperature and electrical resistance measurements. The temperature and electrical resistance measurements are suitable for component applications and provide an enormous advantage of information about the fatigue behavior. The temperature changes of the failed areas of the samples with tension screw geometry were significantly higher, a reliable identification of endangered areas is thereby possible. A new test procedure, developed at the Institute of Materials Science and Engineering of the University of Kaiserslautern, with inserted load-free-states during constant amplitude loading, provides the opportunity to detect proceeding fatigue damage in components during inspections. [source] New Metallic Glass/Alloy (MeGA) Rods Produced by Co-extrusion,ADVANCED ENGINEERING MATERIALS, Issue 10 2006S. Gravier New Metallic Glass/Alloy (MEGA)-rods with a core in bulk metallic glass (zirconium or magnesium based BMG) and a sleeve in conventional light alloys (Al-5056 and Mg-AZ31) have been elaborated by co-extrusion carried out at temperatures corresponding to the supercooled liquid region of the glass. For most glass/alloy combinations, this process leads to defect-free interfaces and therefore to good compressive strengths which can be described by the rule of mixtures. [source] Microwells with Patterned Proteins by a Self-Assembly Process Using Honeycomb-Structured Porous Films,ADVANCED MATERIALS, Issue 18 2008EunHee Min Reactive honeycomb-structured porous films are obtained using amphiphilic block copolymer microwells. This one-step process leads to high functionality inside the pores suitable for the attachement of proteins. As a result, a regular streptavidin array is created by using simple breath figure methology (see figure). [source] Neural bandwidth allocation function (NBAF) control scheme at WiMAX MAC layer interfaceINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 9 2007Mario Marchese Abstract The paper proposes a bandwidth allocation scheme to be applied at the interface between upper layers (IP, in this paper) and Medium Access Control (MAC) layer over IEEE 802.16 protocol stack. The aim is to optimally tune the resource allocation to match objective QoS (Quality of Service) requirements. Traffic flows characterized by different performance requirements at the IP layer are conveyed to the IEEE 802.16 MAC layer. This process leads to the need for providing the necessary bandwidth at the MAC layer so that the traffic flow can receive the requested QoS. The proposed control algorithm is based on real measures processed by a neural network and it is studied within the framework of optimal bandwidth allocation and Call Admission Control in the presence of statistically heterogeneous flows. Specific implementation details are provided to match the application of the control algorithm by using the existing features of 802.16 request,grant protocol acting at MAC layer. The performance evaluation reported in the paper shows the quick reaction of the bandwidth allocation scheme to traffic variations and the advantage provided in the number of accepted calls. Copyright © 2006 John Wiley & Sons, Ltd. [source] Do mergers spin-up dark matter haloes?MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY: LETTERS (ELECTRONIC), Issue 1 2007Elena D'Onghia ABSTRACT We use a large cosmological N -body simulation to study the origin of possible correlations between the merging history and spin of cold dark matter haloes. In particular, we examine claims that remnants of major mergers tend to have higher-than-average spins, and find that the effect is driven largely by unrelaxed systems: equilibrium dark matter haloes show no significant correlation between spin and merging history. Out-of-equilibrium haloes have, on average, higher spin than relaxed systems, suggesting that the virialization process leads to a net decrease in the value of the spin parameter. We find that this decrease is due to the internal redistribution of mass and angular momentum that occurs during virialization. This process is especially efficient during major mergers, when high angular momentum material is pushed beyond the virial radius of the remnant. Because such redistribution likely affects the angular momentum of baryons and dark matter unevenly, our findings question the common practice of identifying the specific angular momentum content of a halo with that of its embedded luminous component. Further work is needed to elucidate the true relation between the angular momentum content of baryons and dark matter in galaxy systems assembled hierarchically. [source] The draw ratio,Deborah number diagram: A useful tool for coating applicationsPOLYMER ENGINEERING & SCIENCE, Issue 3 2006S. Bourrigaud The understanding of the basic physical effects of viscoelasticity on drawing performances in the coating process leads to a useful approach to link the rupture of the polymer melt to critical processing conditions. In particular, we show that when solving the drawing problem in the air gap with a simple constitutive equation,like the upper convected Maxwell model,a mathematical inconsistency appears for some drawing parameters. This mathematical instability may be experimentally correlated to the occurrence of melt-rupture, giving rise to a discussion on the effect of viscoelastic properties on drawing performances. Results are given in terms of a diagram representing the maximum drawing ratio Dr with respect to the Deborah number De. A master curve, obtained form experimental results, accounts for the temperature, melt-index, air-gap height, and extrusion output dependences. The limitations of the "universality" of the concept are discussed later. POLYM. ENG. SCI. 46:372,380, 2006. © 2006 Society of Plastics Engineers [source] Product Technology Transfer in the Upstream Supply ChainTHE JOURNAL OF PRODUCT INNOVATION MANAGEMENT, Issue 6 2003Mohan V. Tatikonda This article addresses the transfer of new product technologies from outside the firm for integration into a new product system as part of a product development effort. Product technology transfer is a key activity in the complex process of new product development and is the fundamental link in the technology supply chain. Product technology transfer too often is dealt with in an ad-hoc fashion. Purposeful management of the product technology transfer process leads to more effective transfers in terms of timeliness, cost, functional performance, and competence building. Better management of product technology transfer gives firms access to a greater variety of new technology options, improves a firm's ability to offer significantly differentiated products, deepens the firm's competitive competencies, and positively influences sustained product development success. The central objective of this article is to gain insight into product technology transfer so that companies can manage this process more successfully and so that researchers can investigate this critical activity further. This article describes the technology supply chain as a unique form of a supply chain that poses a set of managerial challenges and requirements distinguishing it from the more traditional component supply chain. Because a single product technology transfer project is the fundamental piece in the technology supply chain, understanding this piece well is key to leveraging the extended technology supply chain and to improving overall product development performance. This article integrates literatures on new product development, supply chain management, and technology management and builds on organizational theory to present a conceptual model of determinants of product technology transfer success. The core proposition is that product technology transfer effectiveness is greatest when companies carefully match (or "fit") the type of technology to be transferred (the "technology uncertainty") with the type of relationship between the technology supplier and recipient (the "interorganizational interaction"). A quite detailed framework characterizing technology uncertainty along the dimensions of technology novelty, complexity, and tacitness is presented to help in assessing the challenges associated with transferring a particular product technology. This article also considers detailed elements characterizing the interorganizational interactions between the technology source and recipient firms. This helps firms consider the appropriate means to facilitate the interfirm process of technology transfer. Overall, this article provides practical insight into characterizing technologies and into improving the product technology transfer process. This article also provides a strong theoretical foundation to aid future research on product technology transfer in the technology supply chain. [source] Metal-stabilized rare tautomers: N4 metalated cytosine (M = Li+, Na+, K+, Rb+ and Cs+), theoretical viewsAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 8 2003Majid Monajjemi Abstract Ab initio calculations indicate that metalation of the exocyclic amino group of cytosine by the elements of Group IA (Li, Na, K, Rb and Cs) induces protonation of a nucleobase ring nitrogen atom, and hence causes a proton shift from an exocyclic to an endocyclic nitrogen atom. Thus, this metal-assisted process leads to the generation of rare nucleobase tautomers. The calculations suggest that this kind of metalation increases the protonation energies of the aromatic ring of the nucleobase. The present study reports the quantum chemistry analysis of the metal-assisted tautomerization. The calculations clearly demonstrate that metalation of the exocyclic amino group of the nucleobase significantly increases the protonation energy of the aromatic rings of the nucleobase. Also, absolute anisotropy shift, molecular orbital and natural bond orbital calculations are compatible with these results. Copyright © 2003 John Wiley & Sons, Ltd. [source] The properties of fossil groups of galaxiesASTRONOMISCHE NACHRICHTEN, Issue 9-10 2009P. Eigenthaler Abstract Numerical simulations as well as optical and X-ray observations over the last few years have shown that poor groups of galaxies can evolve to what is called a fossil group. Dynamical friction as the driving process leads to the coalescence of individual galaxies in ordinary poor groups leaving behind nothing more than a central, massive elliptical galaxy supposed to contain the merger history of the whole group. Due to merging timescales for less-massive galaxies and gas cooling timescales of the X-ray intragroup medium exceeding a Hubble time, a surrounding faint-galaxy population having survived this galactic cannibalism as well as an extended X-ray halo similar to that found in ordinary groups, is expected. Recent studies suggest that fossil groups are very abundant and could be the progenitors of brightest cluster galaxies (BCGs) in the centers of rich galaxy clusters. However, only a few objects are known to the literature. This article aims to summarize the results of observational fossil group research over the last few years and presents ongoing work by the authors. Complementary to previous research, the SDSS and RASS surveys have been cross-correlated to identify new fossil structures yielding 34 newly detected fossil group candidates. Observations with ISIS at the 4.2 m William Herschel Telescope on La Palma have been carried out to study the stellar populations of the central ellipticals of 6 fossil groups. In addition multi-object spectroscopy with VLTs VIMOS has been performed to study the shape of the OLF of one fossil system (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] X-chromosome upregulation and inactivation: two sides of the dosage compensation mechanism in mammalsBIOESSAYS, Issue 1 2009Elena V. Dementyeva Abstract Mammals have a very complex, tightly controlled, and developmentally regulated process of dosage compensation. One form of the process equalizes expression of the X-linked genes, present as a single copy in males (XY) and as two copies in females (XX), by inactivation of one of the two X-chromosomes in females. The second form of the process leads to balanced expression between the X-linked and autosomal genes by transcriptional upregulation of the active X in males and females. However, not all X-linked genes are absolutely balanced. This review is focused on the recent advances in studying the dosage compensation phenomenon in mammals. [source] | |||||||||||||