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Elements
Kinds of Elements Terms modified by Elements Selected AbstractsPROPERTIES of CROSS-LINKED STARCH PRODUCED IN A SINGLE SCREW EXTRUDER WITH and WITHOUT A MIXING ELEMENTJOURNAL OF FOOD PROCESS ENGINEERING, Issue 1 2004M. SEKER ABSTRACT Starch was extruded with sodium hydroxide and sodium trimetaphosphate in order to cross-link it in a single-screw extruder with and without a mixing element at constant screw speed of 90 rpm in the first set of experiments and at similar mean residence time controlled by screw speed in the second set of experiments. For the screw without mixing element in the second set of experiments, screw speed was adjusted to give the similar residence time as the single-screw extruder with mixing element at 220 rpm. Phosphorus content and pasting curves of extrudates showed that starch was cross-linked during extrusion. Replacing the screw without mixing element by the screw with mixing [source] IS FISHING COMPATIBLE WITH ENVIRONMENTAL CONSERVATION: A STOCHASTIC MODEL WITH AN ELEMENT OF SELF-PROTECTIONNATURAL RESOURCE MODELING, Issue 3 2008D. AMI Abstract The purpose of this paper is to introduce the impact of fishing activity on a marine ecosystem. The fishing activity is considered not only through annual harvest but also through a second component, called the degree of protection of the fishery environment. This characterizes the environmental impact of fishing. A stochastic dynamic programming problem is presented in infinite horizon, where a sole owner seeks to maximize a discounted expected profit. The main hypothesis states that the stock,recruitment relationship is stochastic and that both components of the fishing activity have an impact on the probability law of the state of the fishery environment. The optimal fishing policy is obtained and compared with standard models. This optimal policy has the following properties: is not a constant escapement policy and indicates an element of self-protection by the fishery manager. The paper ends with a discussion on the existence of degrees of protection of the fishery environment that take into account the environmental conservation and preservation of economic activity. [source] GOVERNMENT CALLING: PUBLIC SERVICE MOTIVATION AS AN ELEMENT IN SELECTING GOVERNMENT AS AN EMPLOYER OF CHOICEPUBLIC ADMINISTRATION, Issue 4 2008WOUTER VANDENABEELEArticle first published online: 11 JUL 200 The article assesses public service motivation as a possible influence in the attractiveness of government as an employer by embedding it into a person-organization fit framework. First, a theoretical framework is developed and all relevant concepts are discussed. In addition, a set of hypotheses concerning the research question is developed. A sample of 1714 final year masters students demonstrates that the presence of public service motivation positively correlates with the preference for prospective public employers. For government organizations that display a high degree of publicness, the effect of public service motivation as a predictor for employer preference is stronger. Next to building a middle range theory on public service motivation, the article also reveals that public service motivation is present at a pre-entry level. [source] DETECTING CHANGES OF CELTIC GOLD SOURCES THROUGH THE APPLICATION OF TRACE ELEMENT AND Pb ISOTOPE LASER ABLATION ANALYSIS OF CELTIC GOLD COINS*ARCHAEOMETRY, Issue 4 2009C. BENDALL This project follows on from an initial study of Celtic gold coins from the Middle Rhine/Moselle region, which was based on material found at the Martberg, a Late Iron Age/Roman sanctuary and settlement (River Moselle, western Germany; Bendall 2003). The earlier work was expanded to encompass over 100 examples of various other regional Celtic gold coinages from the collection of the Römisch-Germanisches Zentralmuseum, Mainz. The alloy (Au,Ag,Cu) and trace element compositions (in particular Ni, Sb and Pt) were determined by EPMA and LA,ICP,MS, respectively, and their Pb isotope signatures were measured by LA,MC,ICP,MS. Of the 28 trace elements measured, only Ni, Sb and Pt were found to show meaningful variations and so only they are presented here. In particular, differences in the Pt/Au ratios between various groups of earlier coinage (imitations of Philippus and Alexander/Nike staters, Sch. 23 and some early Boian coins) on the one hand, and the majority of the Boian and the southern rainbow cup coinages on the other, indicate a significant difference in the gold sources exploited for these regional coinages. The Pb isotope data confirm previous conclusions that the contribution of gold to the total lead in the Au,Ag,Cu coin alloys can be detected, especially for coins with over 70% gold, and show that possible gold sources include both eastern Mediterranean and Alpine sources. Combining the Pb isotope data with the Pt/Au ratios allows the potential gold sources to be further differentiated. [source] HAPLODIPLOIDY AS AN OUTCOME OF COEVOLUTION BETWEEN MALE-KILLING CYTOPLASMIC ELEMENTS AND THEIR HOSTSEVOLUTION, Issue 4 2004Benjamin B. Normark Abstract Haplodiploidy (encompassing both arrhenotoky and paternal genome elimination) could have originated from coevolution between male-killing endosymbiotic bacteria and their hosts. In insects, haplodiploidy tends to arise in lineages that rely on maternally transmitted bacteria for nutrition and that have gregarious broods in which competition between siblings may occur. When siblings compete, there is strong selection on maternally transmitted elements to kill males. I consider a hypothetical bacterial phenotype that renders male zygotes effectively haploid by preventing chromosome decondensation in male-determining sperm nuclei. By causing high male mortality, such a phenotype can be advantageous to the bacterial lineage. By eliminating paternal genes, it can also be advantageous to the host female. A simple model shows that the host female will benefit under a wide range of values for the efficiency of resource re-allocation, the efficiency of transmission, and the viability of haploid males. This hypothesis helps to explain the ecological correlates of the origins of haplodiploidy, as well as such otherwise puzzling phenomena as obligate cannibalism by male Micromalthus beetles, reversion to diploidy by aposymbiotic male stictococcid scale insects, and the bizarre genomic constitution of scale insect bacteriomes. [source] THE ELEMENTS OF RESPONSIBILITY*ANALYTIC PHILOSOPHY, Issue 3 2005Philip Pettit First page of article [source] ON THE STRONG LAW OF LARGE NUMBERS UNDER REARRANGEMENTS FOR SEQUENCES OF BLOCKWISE ORTHOGONAL RANDOM ELEMENTS IN BANACH SPACESAUSTRALIAN & NEW ZEALAND JOURNAL OF STATISTICS, Issue 4 2007Nguyen Van Quang Summary The condition of the strong law of large numbers is obtained for sequences of random elements in type p Banach spaces that are blockwise orthogonal. The current work extends a result of Chobanyan & Mandrekar (2000)[On Kolmogorov SLLN under rearrangements for orthogonal random variables in a B -space. J. Theoret. Probab. 13, 135,139.] Special cases of the main results are presented as corollaries, and illustrative examples are provided. [source] OVERT AND COVERT NARCISSISM: TURNING POINTS AND MUTATIVE ELEMENTS IN TWO PSYCHOTHERAPIESBRITISH JOURNAL OF PSYCHOTHERAPY, Issue 4 2001Jan Ole Revik ABSTRACT Two patients, one with an overt and the other with a covert narcis-sistic disorder, are followed through five years of psychoanalytic psychotherapy. A number of important turning points in the therapies are closely evaluated in order to discover possible mutative elements. Special attention is paid to the patients' self-sufficiency. The attachment process to the therapist and the patients' gradual acceptance of healthy dependency are described. The theoretical framework is selfpsychological. [source] An Investigation of Localization as an Element of Cognitive Fit in Accounting Model RepresentationsDECISION SCIENCES, Issue 1 2001Cheryl Dunn Abstract Cognitive fit, a correspondence between task and data representation format, has been demonstrated to lead to superior task performance by individual users and has been posited as an explanation for performance differences among users of various problem representations such as tables, graphs, maps, and schematic faces. The current study extends cognitive fit to accounting models and integrates cognitive fit theory with the concept of localization to provide additional evidence for how cognitive fit works. Two accounting model representations are compared in this study, the traditional DCA (Debit-Credit-Account) accounting model and the REA (Resources-Events-Agents) accounting model. Results indicate that the localization of relevant objects or linkages is important in establishing cognitive fit. [source] Microstructure and Transport Properties of Cellular Materials: Representative Volume ElementADVANCED ENGINEERING MATERIALS, Issue 10 2009Emmanuel Brun The representative volume element (RVE) plays a central role in efforts to predict the effective thermo-physical and transport properties of heterogeneous materials. A quantitative definition of its size is proposed in this work. It is shown that RVE depends on the morphological or physical property being investigated. The methodology is applied to real samples of open-celled materials (such as metallic foam) whose structure is obtained from X-Ray microtomography. [source] Design approach for the hybrid underground station at Union Suare/Market Street in San Francisco.GEOMECHANICS AND TUNNELLING, Issue 4 2009Entwurfskonzept für eine hybride U-Bahnstation Union Square/Market Street in San Francisco Abstract The new Central Subway extension through downtown San Francisco consists of three underground stations and 2.7 km TBMdriven twin tunnel. This paper provides a description of the preliminary analyses and design of the ground support and final lining for the Union Square\Market Street Station (UMS) along Stockton Street. This station will serve the Union Square Shopping District and connect to the BART Powell Street Station. Due to shortage of space above ground and to minimize surface disruption, the UMS station design requires a complex hybrid method consisting of a 20 m deep braced cut-and-cover box with a mined enlargement bulb below it with a height of 9.3 m and a width of 17.8 m. The majority of the UMS station will be excavated in saturated alluvial deposits. Undifferentiated old bay deposits will be encountered in the invert, underlain by dense marine sands. The groundwater varies from 5 to 10 m below ground level, so uplift of the combined bulb/box structure has to be taken into account. The Finite Element (FE) analysis of the UMS station cavern reflects the separate construction phases of the station platform box and the bulb to account for soil-structure interaction and load-sharing effects. FE analyses are used to estimate support requirements including ground improvement and to predict surface settlements. Die Erweiterung der Central Subway durch die Innenstadt von San Francisco beinhaltet drei Stationsbauwerke und 2,7 km maschinell vorgetriebene Doppelröhrentunnel. In diesem Artikel erfolgt eine Beschreibung der Voruntersuchungen und Vorbemessung der Stützmaßnahmen sowie der Innenschale der Union Square\Market Street Station (UMS) im Verlauf der Stockton Street. Diese Station soll dem Union Square Shopping Distrikt dienen und zur BART Powell Street Station verbinden. Aufgrund der beengten Platzverhältnisse und zur Minimierung der Beeinträchtigung der Oberfläche ist ein "hybrides" Konzept der UMS-Station erforderlich. Dieses besteht aus einer 20 m tiefen ausgesteiften Baugrube (Box) und einer darunterliegenden bergmännisch hergestellten Kaverne (Bulb) mit 9,3 m Höhe und 17,8 m Breite. Der Großteil der UMS-Station befindet sich in gesättigten alluvialen Ablagerungen. Undifferenziert werden alte Bucht-Ablagerungen und dichte marine Sande in der Sohle vorgefunden. Der Grundwasserspiegel variiert in einer Teufe zwischen 5 bis 10 m unter der Oberfläche, aus diesem Grund ist der Auftrieb des kombinierten Bauwerks bestehend aus Bulb und Box zu berücksichtigen. In Finite Element (FE) Berechnungen der UMS-Station werden die einzelnen Bauphasen des Stationsbauwerks, sowohl von Box als auch Bulb, modelliert, um die Wechselwirkungen von Baugrund-Bauwerk und die jeweiligen Lastumlagerungen zu berücksichtigen. Mittels FE-Berechnungen werden schließlich die notwendigen Stützmaßnahmen , diese beinhalten auch Bodenverbesserungsmaßnahmen , und die Oberflächensetzungen festgelegt. [source] From mixed finite elements to finite volumes for elliptic PDEs in two and three dimensionsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 3 2004Anis Younes Abstract The link between Mixed Finite Element (MFE) and Finite Volume (FV) methods applied to elliptic partial differential equations has been investigated by many authors. Recently, a FV formulation of the mixed approach has been developed. This approach was restricted to 2D problems with a scalar for the parameter used to calculate fluxes from the state variable gradient. This new approach is extended to 2D problems with a full parameter tensor and to 3D problems. The objective of this new formulation is to reduce the total number of unknowns while keeping the same accuracy. This is achieved by defining one new variable per element. For the 2D case with full parameter tensor, this new formulation exists for any kind of triangulation. It allows the reduction of the number of unknowns to the number of elements instead of the number of edges. No additional assumptions are required concerning the averaging of the parameter in hetero- geneous domains. For 3D problems, we demonstrate that the new formulation cannot exist for a general 3D tetrahedral discretization, unlike in the 2D problem. However, it does exist when the tetrahedrons are regular, or deduced from rectangular parallelepipeds, and allows reduction of the number of unknowns. Numerical experiments and comparisons between both formulations in 2D show the efficiency of the new formulation. Copyright © 2003 John Wiley & Sons, Ltd. [source] A Low-Temperature-Grown Oxide Diode as a New Switch Element for High-Density, Nonvolatile Memories,ADVANCED MATERIALS, Issue 1 2007M.-J. Lee A one-diode/one-resistor structure, Pt/NiO/Pt/p-NiOx/n-TiOx/Pt, has been fabricated. This novel structure exhibits bistable resistance switching under forward bias, while the diode suppresses resistance switching in the Pt/NiO/Pt memory cell under reverse bias (see figure). Its low processing temperature and small cell size, as well as excellent rectifying characteristics, make this Pt/p-NiOx/n-TiOx/Pt diode structure a promising switch element for high- density, nonvolatile memory devices with 3D stack and cross-point structures. [source] Immediate implants at fresh extraction sockets: an experimental study in the beagle dog comparing four different implant systems.JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 8 2010Soft tissue findings de Sanctis M, Vignoletti F, Discepoli N, Muñoz F, Sanz M. Immediate implants at fresh extraction sockets: an experimental study in the beagle dog comparing four different implant systems. Soft tissue findings. J Clin Periodontol 2010; 37: 769-776 doi: 10.1111/j.1600-051X.2010.01570.x. Abstract Objectives: To evaluate whether different implants placed immediately upon tooth extraction may affect the dimension and composition of the peri-implant soft tissues. Material and Methods: Eight beagle dogs received implants randomly installed into the distal socket of 3P3 and 4P4. Four commercially available implant systems were evaluated: 3i Osseotite Certain straight; Astra MicroThreadÔ -OsseoSpeedÔ; Thommen SPI Element®; and Straumann ITI standard. Each animal provided four test implant sites. All animals were sacrificed 6 weeks after implant placement, providing specimens for the evaluation of the soft tissue dimensions by histometric analysis. Results: The biological width at 6 weeks after implant placement consisted of a junctional epithelium measuring between 2 and 2.7 mm and a connective tissue component between 1 and 1.8 mm with no statistical differences among the four implant systems. Conclusion: This study failed to demonstrate differences in the soft tissue healing outcome when placing four different implant systems into fresh extraction sockets. Nevertheless, the length of the epithelium achieved with the four implant systems is longer than what has been reported when placing implants in healed-ridge experimental models. [source] Location of Caspase 3-like Protease in the Development of Sieve Element and Tracheary Element of Stem in Cucurbita moschataJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 12 2008Xia Hao Abstract The casepase is considered to regulate the process of programmed cell death in the development of organisms. In this study, caspase 3-like protease was detected by immunohistochemistry and immunoelectron microscopy during the development of sieve element and tracheary element of stem in Cucurbita moschata Duch. Antibody with brown color (under light microscopy) and gold particles (under transmission electron microscopy) for detecting caspase 3-like protease was mainly displayed in inner phloem, external phloem and xylem in the region close to procambium. From the results it was considered that caspase 3-like protease did exist in vascular elements and played different roles during the development of sieve and tracheary elements, and different types of programmed cell death might be carried out. The caspase 3-like protease mainly participated in making cytoplasmic streaming cease and in degrading P-protein bodies; however, it rarely participated in the function for signal transferring in the developmental sieve element. However, it might induce calcium accumulation for rupturing the tonoplast in the signal of PCD in the developmental tracheary element. [source] Eisen-, Calcium- und Magnesium-Salze.PHARMAZIE IN UNSERER ZEIT (PHARMUZ), Issue 3 2009Chemie und Eigenschaften Zusammenfassend lässt sich sagen, dass Calcium, Magnesium und Eisen in der modernen Pharmazie in den unterschiedlichsten Bereichen vorkommen. Besonders der menschliche Organismus reagiert sehr sensibel auf Schwankungen und einen Mangel am jeweiligen Element. Die Stoffwechselvorgänge im Körper sind somit stark abhängig von einer konstanten Homöostase. Für die Therapie einer Mangelerscheinung ist die Auswahl des richtigen Präparats unumgänglich, wobei sich viele grundlegende Eigenschaften der eingesetzten Mineralpräparate leicht aus den chemischen Grundkenntnissen ableiten lassen. [source] Effective Dynamic Material Properties of Foam-like MicrostructuresPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2005S. Alvermann The effective material parameters of a microstructured material can be found using homogenization procedures based on calculations of a Representative Volume Element (RVE) of the material. In our approach the RVE is calculated in frequency domain and inertia is taken into account, leading to a frequency dependent behavior of the RVE. With the frequency response of the RVE, effective dynamic properties of the material are calculated using an optimization procedure. Due to the frequency dependent material behavior on the microscale a viscoelastic constitutive equation is applied on the macroscale. An example calculation is presented for an auxetic 2-D foam-like microstructure which is modelled as a plane frame structure. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Classes of Anisotropic Finite Plasticity Models and their Implementation in a Brick-Type Shell ElementPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2003N. Apel We discuss two constitutive models formulated in terms of logarithmic strains suitable for the description of elastoplastic material response. We consider two different approaches to the definition of the plastic deformation. The first is based on the introduction of a plastic map yielding a multiplicative decomposition of the deformation gradient into an elastic and plastic part. The second one uses an additive decomposition of the current metric. A quantitative analysis of both approaches by means of numerical examples of sheet metal forming processes are presented. [source] Synchronicity and moments of meetingTHE JOURNAL OF ANALYTICAL PSYCHOLOGY, Issue 2 2009George B. Hogenson Abstract:, The paper, considers the role of synchronicity in the establishment of meaning in analysis, and links it to the notion of moments of meeting proposed by the Boston Process of Change Study Group. In so doing, the paper proposed to view synchronicity as an element in developmental processes, wherein attributions of meaningfulness are made in relation to patterns of action that do not have intrinsic meaning, but which have evolved in an environment of meaning, thereby bootstrapping the infant into the world of meaning. Jung's paradigmatic example of synchronicity,the scarab beetle event,is examined in this context and the argument is made that the event was primarily meaningful for Jung and carried with it important countertransference implications that Jung did not consider. The paper concludes with some suggestions for further investigation into the relationship between synchronicity and clinical practice. Translations of Abstract Cet article étudie le rôle de la synchronicité dans l'établissement du sens en analyse. L'auteur met cette notion en rapport avec celle de ,moments de rencontre', proposée par le Boston Process of Change Study Group (Groupe d'études sur les processus de changement de Boston). Ce faisant, l'article propose d'envisager la synchronicité comme un élément du processus de développement, au cours duquel l'attribution de sens s'effectue en référence à des patterns d'action ne possédant pas de sens intrinsèque mais inclus dans un environnement sémantique. Le petit enfant est ainsi pousséà se débrouiller dans le monde du sens. L'exemple paradigmatique de Jung,l'épisode du scarabée,est examiné dans ce contexte; l'auteur affirme que cet épisode était avant tout doté de sens pour Jung lui-même et qu'il était porteur d'implications contre-transférentielles dont celui-ci ne tint pas compte. L'article propose en guise de conclusion quelques pistes de réflexion sur la question de la relation entre synchronicité et pratique clinique. Diese Arbeit untersucht die Rolle der Synchronizität bei der Gewinnung von Bedeutungszusammenhängen in der Analyse und verbindet sie mit dem Begriff der Momente der Begegnung, wie er von der Bostoner Studiengemeinschaft, die sich mit dem Thema der Wandlungsprozesse beschäftigt, entworfen wurde. Hierbei wird der Vorschlag entwickelt, Synchronizität als ein Element in Entwicklungsprozessen zu sehen, in denen Attribute der Bedeutungshaftigkeit in Beziehung gesetzt werden zu Handlungsmustern, denen keine intrinsische Bedeutung zukommt, die sich jedoch in einem Bedeutungsumfeld entwickelt haben, und durch die das Kind in eine Welt von Bedeutungen eingeführt wird. Jungs paradigmatisches Beispiel für Synchronizität,das Skarabäus-Ereignis,wird in seinem Kontext überprüft und die Behauptung aufgestellt, daß das Ereignis primär bedeutungsvoll für Jung gewesen sei und insofern wichtige Implikationen einer Gegenübertragung beinhaltete, die Jung nicht in Betracht zog. Der Text schließt mit einigen Vorschlägen für zukünftige Untersuchungen bezüglich des Verhältnisses von Synchronizität und klinischer Praxis. In questo lavoro si considera il ruolo della sincronicità nella costruzione di significato in analisi e ci si collega alla nozione di momenti di significato proposta dal Boston Process of Change Study Group. Così facendo in questo scritto si propone di considerare la sincronicità come un elemento di processi evolutivi, nei quali le attribuzioni di valenza significativa sono fatte in relazione a schemi di azione che non hanno significato intrinseco, ma che si sono evolute in un ambiente significativo, inserendo così il bambino nel mondo del significato. Viene poi esaminato in questo contesto il paradigmatico esempio di sincronicità fatto da Jung,l'evento dello scarabeo,e si sostiene che l'evento fu considerato significativo primariamente da Jung e portò con sé importanti implicazioni controtransferali che Jung non considerò. Questo lavoro si conclude con alcune considerazioni per ulteriori approfondimenti sulla relazione tra sincronicità e pratica clinica. El trabajo explora el papel de la sincronicidad en el establecimiento de significado en el análisis, y lo liga a la noción de momentos de encuentro propuesta por el Grupo de Estudio de Boston Sobre el Proceso de Cambio. Al hacerlo, el trabajo propone ver a la sincronicidad como un elemento en procesos de desarrollo, en donde se atribuyen condiciones llenas de sentido en relación con pautas de acción que no tienen coherencia intrínseca, pero que han evolucionado en un ambiente lleno de significado, gracias al cual el niño es conducido en el mundo del sentido. Se examina el ejemplo paradigmático de Jung de la sincronicidad,el acontecimiento del escarabajo,en este contexto y se argumenta que el acontecimiento fue principalmente significativo para Jung y contenía implicaciones contratransferenciales importantes que Jung no consideró. El estudio concluye con algunas sugerencias adicionales para la investigación de la relación entre la sincronicidad y la práctica clínica. [source] Cooling Device for Bradycardia Based on Peltier Element for Accurate Anastomosis of Off-Pump Coronary Artery Bypass GraftingARTIFICIAL ORGANS, Issue 10 2002Yukio Kuniyoshi Abstract: Upon introducing off-pump coronary artery bypass grafting (CABG), the indications for CABG were expanded to include patients who previously had no operative indications. For accurate anastomosis, various devices and methods have been developed. Bradycardia is easily induced by drug administration. However, this method of achieving bradycardia also has adverse effects on cardiac function. We have developed a new device to decrease the heart rate by regional cooling of the sino-atrial node. The new device is incorporated with Peltier's element, which uses an electric charge to create a temperature gradient on both of its surfaces. In terms of the cooling ability of this device, its cooling surface is chilled from 25°C to 0°C within 30 s. During in vivo animal experiments, this device has been shown to decrease the myocardial temperature around the sino-atrial node to 15°C and suppress sino-atrial node activity, resulting in bradycardia to 60 beats/min level. In summary, the simple and easily applicable device for local cooling in combination with the application of diltiazem for effective heart rate reduction may be very helpful for the surgeon and may avoid disadvantages for critically ill patients. [source] Regulatory mechanisms of intestinal iron absorption,Uncovering of a fast-response mechanism based on DMT1 and ferroportin endocytosisBIOFACTORS, Issue 2 2010Marco T. Núñez Abstract Knowledge on the intestinal iron transport process and the regulation of body iron stores has greatly increased during the last decade. The liver, through the sensing of circulating iron, is now recognized as the central organ in this regulation. High iron levels induce the synthesis of hepcidin, which in turn decreases circulating iron by inhibiting its recycling from macrophages and its absorption at the intestine. Another mechanism for the control of iron absorption by the enterocyte is an active Iron Responsive Element (IRE)/Iron Regulatory Protein (IRP) system. The IRE/IRP system regulates the expression of iron uptake and storage proteins thus regulating iron absorption. Similarly, increasing evidence points to the transcriptional regulation of both divalent metal transporter 1 (DMT1) and ferroportin expression. A new mechanism of regulation related to a phenomenon called the mucosal block is starting to be unveiled. The mucosal block describes the ability of an initial dose of ingested iron to block absorption of a second dose given 2,4 h later. Here, we review the mechanisms involved in the expression of DMT1 and ferroportin, and present recent evidence on the molecular components and cellular processes involved in the mucosal block response. Our studies indicate that mucosal block is a fast-response endocytic mechanism destined to decrease intestinal iron absorption during a high ingest of iron. [source] Review modeling the free solution and gel electrophoresis of biopolymers: The bead array-effective medium modelBIOPOLYMERS, Issue 2-3 2007Stuart A. Allison Abstract Free solution and gel electrophoresis is an extremely useful tool in the separation of biopolymers. The complex nature of biopolymers, coupled with the usefulness of electrophoretic methods, has stimulated the development of theoretical modeling over the last 30 years. In this work, these developments are first reviewed with emphasis on Boundary Element and bead methodologies that enable the investigator to design realistic models of biopolymers. In the present work, the bead methodology is generalized to include the presence of a gel through the Effective Medium model. The biopolymer is represented as a bead array. A peptide, for example, made up of N amino acids is modeled as 2N beads. Duplex DNA is modeled as a discrete wormlike chain consisting of touching beads. The technical details of the method are placed in three Appendices. To illustrate the accuracy and effectiveness of the approach, two applications are considered. Model studies on both the free solution mobility of 73 peptides ranging in size from 2 to 42 amino acids, and the mobility of short duplex DNA in dilute agarose gels are discussed. © 2007 Wiley Periodicals, Inc. Biopolymers 87: 102,114, 2007. This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source] Rare Earth Element and Trace Element Features of Gold-bearing Pyrite in the Jinshan Gold Deposit, Jiangxi ProvinceACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 3 2010Guangzhou MAO Abstract: Jinshan gold deposit is located in northeastern Jiangxi, South China, which is related to the ductile shear zone. It has a gold reserve of more than 200 tons, with 80% of gold occurring in pyrite. The ,REE of gold-bearing pyrite is as higher as 171.664 ppm on average, with relatively higher light rare earth elements (LREE; 159.556 ppm) and lower HREE (12.108 ppm). The ,LREE/,HREE ratio is 12.612 and (La/Yb)N is 11.765. These indicate that pyrite is rich in LREE. The (La/Sm)N ratio is 3.758 and that of (Gd/Yb)N is 1.695. These are obvious LREE fractionations. The rare earth element (REE) distribution patterns show obvious Eu anomaly with average ,Eu values of 0.664, and ,Ce anomalies of 1.044. REE characteristics are similar to those of wall rocks (regional metamorphic rocks), but different from those of the Dexing granodiorite porphyry and Damaoshan biotite granite. These features indicate that the ore-forming materials in the Jinshan gold deposit derived from the wall rocks, and the ore-forming fluids derived from metamorphic water. The Co/Ni ratio (average value 0.38) of pyrite suggests that the Jinshan gold deposit formed under a medium,low temperature. It is inferred from the values of high-field strength elements, LREE, Hf/Sm, Nb/La, and Th/La of the pyrite that the ore-forming fluids of the Jinshan gold deposit derived from metamorphic water with Cl>F. [source] Phase Equilibria Constraints on Relations of Ore-bearing Intrusions with Flood Basalts in the Panxi Region, Southwestern ChinaACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 2 2009Zhaochong ZHANG Abstract: There are two types of temporally and spatially associated intrusions within the Emeishan large igneous province (LIP); namely, small ultramafic subvolcanic sills that host magmatic Cu-Ni-Platinum Group Element (PGE)-bearing sulfide deposits and large mafic layered intrusions that host giant Ti-V magnetite deposits in the Panxi region. However, except for their coeval ages, the genetic relations between the ore-bearing intrusions and extrusive rocks are poorly understood. Phase equilibria analysis (Q-Pl-Ol-Opx-Cpx system) has been carried out to elucidate whether ore-bearing Panzhihua, Xinjie and Limahe intrusions are co-magmatic with the picrites and flood basalts (including high-Ti, low-Ti and alkali basalts), respectively. In this system, the parental magma can be classified as silica-undersaturated olivine basalt and silica-saturated tholeiite. The equivalents of the parental magma of the Xinjie and Limahe peridotites and picrites and low-Ti basalts are silica-undersaturated, whereas the Limahe gabbro-diorites and high-Ti basalts are silica-saturated. In contrast, the Panzhihua intrusion appears to be alkali character. Phase equilibria relations clearly show that the magmas that formed the Panzhihua intrusion and high-Ti basalts cannot be co-magmatic as there is no way to derive one liquid from another by fractional crystallization. On the other hand, the Panzhihua intrusion appears to be related to Permian alkali intrusions in the region, but does not appear to be related to the alkali basalts recognized in the Longzhoushan lava stratigraphy. Comparably, the Limahe intrusion appears to be a genetic relation to the picrites, whereas the Xinjie intrusion may be genetically related to be low-Ti basalts. Additionally, the gabbro-diorites and peridotites of the Limahe intrusion are not co-magmatic, and the former appears to be derived liquid from high-Ti basalts. [source] Aminoglycoside,Quinacridine Conjugates: Towards Recognition of the P6.1 Element of Telomerase RNACHEMBIOCHEM, Issue 2 2006Markus Kaiser Dr. Abstract A modular synthesis has been developed which allows easy and rapid attachment of one or two aminoglycoside units to a quinacridine intercalator, thereby leading to monomeric and dimeric conjugates. Melting temperature (Tm) experiments show that the tobramycin dimeric conjugate TD1 exhibits strong binding to the P6.1 element of human telomerase RNA. By contrast, tobramycin alone is much less efficient and the monomeric compound TM1 elicits a poor binding ability. Monitoring of the interaction by an electrophoretic mobility shift assay shows a 1:1 stoichiometry for the binding of the dimeric compound to the hairpin structure and confirms the lower affinity for a control duplex. Protection experiments with RNase T1 indicate interaction of the drug both in the stem and in the loop of the hairpin. Taken together, the data suggest a binding of TD1 inside the hairpin at the stem-loop junction. The same trends are observed with paromomycin and kanamycin analogues but with a lower affinity. [source] ChemInform Abstract: Ladders of a Magnetically Active Element in the Structure of the Novel Complex Boride Ti9Fe2Ru18B8: Synthesis, Structure, Bonding, and Magnetism.CHEMINFORM, Issue 27 2008Boniface P. T. Fokwa Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] The First Reduced Rare Earth Halide with a Group 11 Element as Interstitial: La3I3Au.CHEMINFORM, Issue 6 2005Hansjuergen Mattausch Abstract For Abstract see ChemInform Abstract in Full Text. [source] Phosphorus Nanorods , Two Allotropic Modifications of a Long-Known Element.CHEMINFORM, Issue 41 2004Arno Pfitzner Abstract For Abstract see ChemInform Abstract in Full Text. [source] Disproportionation of an Element in a Zeolite.CHEMINFORM, Issue 52 2003Part 2. Abstract For Abstract see ChemInform Abstract in Full Text. [source] Stereoretentive O- to -C Rearrangement of Vinyl Acetals: Solvent Cage Effects as a Stereocontrol Element.CHEMINFORM, Issue 51 2002Yongda Zhang Abstract For Abstract see ChemInform Abstract in Full Text. [source] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||