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System Capable (system + capable)
Selected AbstractsKnowledge-based Diagnosis Aiding in Regulation ThermographyPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2003Hagen Knaf Dr. Regulation Thermography is a diagnostic tool in the medical science based on the measurement of the body's thermoregulation ability , the so-called thermogram. The expert's rules for the interpretation of a thermogram can be modelled using Fuzzy Logic. In the present article this modelling process is briefly explained; it leads to a Fuzzy Inference System capable of evaluating thermograms with respect to e.g. signals for the presence of Breast Cancer. Some of the main points of a comparison between the expert rules and the result of a stepwise linear discriminant analysis performed on classified thermograms are presented. [source] On-chip tryptic digest with direct coupling to ESI-MS using magnetic particlesELECTROPHORESIS, Issue 24 2008Anne Le Nel Abstract As a step toward a fully automated front-end microfluidic chip for MS proteomics, we propose a system capable of performing online tryptic digest and ESI-MS, using a replaceable on-chip digestion microcolumn based on self-assembled magnetic particles. [source] Microautosamplers for discrete sample injection and dispensationELECTROPHORESIS, Issue 9 2005Chun-Wei Huang Abstract Microfluidic systems show considerable potential for use in the continuous reaction and analysis of biosamples for various applications, such as drug screening and chemical synthesis. Typically, microfluidic chips are externally connected with large-scale autosamplers to inject specific volumes of discrete samples in the continuous monitoring and analysis of multiple samples. This paper presents a novel microelectromechanical system (MEMS)-based autosampler capable of performing the discrete injection and dispensation of variable-volume samples. This microdevice can be integrated with other microfluidic devices to facilitate the continuous monitoring and analysis of multiple biosamples. By means of electroosmotic focusing and switching controlled by the direct application of electric sources on specific fluid reservoirs, a precise sample volume can be injected into the specified outlet port. Fluorescence dye images verify the performance of the developed device. An injection-and-washing scheme is developed to prevent cross-contamination during the continuous injection of different samples. This approach renders feasible the injection of several discrete samples using a single microchip. Compared to its large-scale counterparts, the developed microautosampler is compact in size, has low fabrication costs, is straightforward to control, and most importantly, is readily integrated with other microfluidic devices (e.g., microcapillary electrophoresis chips) to form a microfluidic system capable of the continuous monitoring and analysis of bioreactions. The proposed microautosampler could be promising towards realizing the micrototal analysis system (,-TAS) concept. [source] Genetic diversity and migration patterns of the aquatic macrophyte Potamogeton malaianus in a potamo-lacustrine systemFRESHWATER BIOLOGY, Issue 6 2009YUANYUAN CHEN Summary 1.,Previously, the Yangtze River connected thousands of shallow lakes which together formed a potamo-lacustrine system capable of sustaining a rich variety of submerged macrophytes. 2.,Potamogeton malaianus is one of the dominant submerged macrophytes in many lakes of this area. Genetic variation and population structure of P. malaianus populations from ten lakes in the potamo-lacustrine system were assessed using inter-simple sequence repeat markers. 3.,Twelve primer combinations produced a total of 166 unambiguous bands of which 117 (70.5%) were polymorphic. Potamogeton malaianus exhibited a moderate level of population genetic diversity (PP = 70.5%, HE = 0.163 and I = 0.255), as compared with that of plants in the same habitat and range. The main factors responsible for this moderate value were the plant's mixed breeding system (both sexual and asexual) and the hydrological connectivity among habitats. 4.,F statistics, calculated using different approaches, consistently revealed a moderate genetic differentiation among populations, contributing about 20% of total genetic diversity. An estimate of gene flow (using FST) suggested that gene flow played a more important role than genetic drift in the current population genetic structure of P. malaianus (Nm = 1.131). 5.,The genetic diversity of P. malaianus did not increase downstream. A high level of linkage,disequilibrium at the whole population level suggested that metapopulation processes may affect genetic structure. The migration pattern of P. malaianus was best explained by a two-dimensional stepping stone model, indicating that bird-mediated dispersal could greatly influence gene movements among lakes. [source] Corporate Governance in IndiaJOURNAL OF APPLIED CORPORATE FINANCE, Issue 1 2008Rajesh Chakrabarti The Indian corporate governance system has both supported and held back India's ascent to the top ranks of the world's economies. While on paper the country's legal system provides some of the best investor protection in the world, enforcement is a major problem, with overburdened courts and significant corruption. Ownership remains concentrated and family business groups continue to be the dominant business model, with significant pyramiding and evidence of tunneling activity that transfers cash flow and value from minority to controlling shareholders. But for all its shortcomings, Indian corporate governance has taken major steps toward becoming a system capable of inspiring confidence among institutional and, increasingly, foreign investors. The Securities and Exchanges Board of India (SEBI), which was established as part of the comprehensive economic reforms launched in 1991, has made considerable progress in becoming a rigorous regulatory regime that helps ensure transparency and fair practice. And the National Stock Exchange of India, also established as part of the reforms, now functions with enough efficiency and transparency to be generating the third-largest number of trades in the world, just behind the NASDAQ and NYSE. Among more recent changes, the enactment of Sarbanes,Oxley type measures in 2004,which includes protections for minority shareholders in family- or "promoter"-led businesses,has contributed to recent increases in institutional and foreign stock ownership. And while family- and government-controlled business groups continue to be the rule, India has also seen the rise of successful companies like Infosys that are free of the influence of a dominant family or group and have made the individual shareholder their central governance focus. [source] Mechanobiological response of tendon stem cells: Implications of tendon homeostasis and pathogenesis of tendinopathyJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 5 2010Jianying Zhang Abstract Tendons are constantly subjected to mechanical loading in vivo. Recently, stem cells were identified in human, mouse, and rabbit tendons, but the mechanobiological responses of tendon stem cells (TSCs) are still undefined. Using an in vitro system capable of mimicking in vivo loading conditions, it was determined that mechanical stretching increased TSC proliferation in a stretching magnitude-dependent manner. Moreover, low mechanical stretching at 4% ("clamp-to-clamp" engineering strain) promoted differentiation of TSCs into tenocytes, whereas large stretching at 8% induced differentiation of some TSCs into adipogenic, chondrogenic, and osteogenic lineages, as indicated by upregulated expression of marker genes for adipocytes, chondrocytes, and osteocytes. Thus, low mechanical stretching may be beneficial to tendons by enabling differentiation of TSCs into tenocytes to maintain tendon homeostasis. However, large mechanical loading may be detrimental, as it directs differentiation of TSCs into non-tenocytes in tendons, thus resulting in lipid accumulation, mucoid formation, and tissue calcification, which are typical features of tendinopathy at later stages. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:639,643, 2010 [source] Investigation of impinging-jet crystallization with a calcium oxalate model systemAICHE JOURNAL, Issue 9 2003Jean M. Hacherl An impinging-jet crystallizer was investigated in this work to assess its operational sensitivity and reproducibility for the production of small, monodisperse crystals using calcium oxalate, a model system capable of forming multiple hydrates. The impinging-jet mixer provides rapid mixing of the reactant solutions through the impingement of two narrow reactant streams at high velocity. Impinging jet linear velocity and postjetting conditions were studied, with the jet operated in nonsubmerged mode. Hydrate form and crystal-size distribution (CSD) were determined using optical microscopy and image analysis techniques. The impinging jet consistently produced small, monodisperse crystals. However, at a high level of supersaturation, slight variations in the CSD were observed for apparently identical conditions, suggesting a degree of sensitivity in the system that could lead to difficulty in its application. An apparent trend between impinging-jet linear velocity and crystal size and number was observed, with more small crystals produced at higher linear velocity. [source] High-resolution imaging of progressive articular cartilage degenerationJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 4 2006Samuel B. Adams Jr Abstract The objective of this study was to develop and verify a new technique for monitoring the progression of osteoarthritis (OA) by combining a rat model with the imaging modality optical coherence tomography (OCT). Time-sequential, in vivo, OCT imaging was performed on the left femoral condyles of 12 Wistar rats following sodium,iodoacetic acid-induced OA progression. The right femoral condyles (untreated) were also imaged and served as controls. Imaging was performed on days 0, 10, 20, 30, and 60 with an OCT system capable of acquiring images at four frames per second and an axial resolution of 5 µm. Progressive changes were analyzed using an OA scoring system. OCT successfully identified progressive cartilage degeneration as well as alteration of the cartilage/bone interface. Significant changes to both of these structures were observed in the sodium,iodoacetic acid-injected condyles. Structural changes detected with OCT were confirmed histologically. OCT in combination with a well-known model used in arthritis research represents a powerful tool for following degenerative joint disease progression in a given animal by detecting changes to the cartilage/bone interface and articular cartilage. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res [source] A systematic approach for the generation and verification of structural hypothesesMAGNETIC RESONANCE IN CHEMISTRY, Issue 5 2009Mikhail Elyashberg Abstract During the process of molecular structure elucidation the selection of the most probable structural hypothesis may be based on chemical shift prediction. The prediction is carried out using either empirical or quantum-mechanical (QM) methods. When QM methods are used, NMR prediction commonly utilizes the GIAO option of the DFT approximation. In this approach the structural hypotheses are expected to be investigated by scientist. In this article we hope to show that the most rational manner by which to create structural hypotheses is actually by the application of an expert system capable of deducing all potential structures consistent with the experimental spectral data and specifically using 2D NMR data. When an expert system is used the best structure(s) can be distinguished using chemical shift prediction, which is best performed either by an incremental or neural net algorithm. The time-consuming QM calculations can then be applied, if necessary, to one or more of the ,best' structures to confirm the suggested solution. Copyright © 2009 John Wiley & Sons, Ltd. [source] Internal wideband monopole antenna for MIMO access-point applications in the WLAN/WIMAX bandsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 5 2008Jui-Hung Chou Abstract A three-antenna MIMO system capable of generating a wide operating bandwidth of 2400,5850 MHz for access-point applications is introduced. The proposed design is based on a bent metal-plate monopole antenna with a compact size of 20 × 20 × 14 mm3. The three antennas are equally spaced along the perimeter of a circular ground and all generate a wide bandwidth of larger than 4 GHz. With the antenna short-circuiting facing the center of the ground, not only the overall antenna size is reduced but also good isolation of less than ,20 dB can easily be obtained. Calculated envelope correlation is also less than 0.002 across the operating band. The design prototype of the antenna is discussed in detail in the article. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1146,1148, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23333 [source] The Monolithic Fetal Pacemaker:PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 4p1 2003Prototype Lead Design for Closed Thorax Deployment DELL'ORFANO, J., et al.: The Monolithic Fetal Pacemaker: Prototype Lead Design for Closed Thorax Deployment.Prenatal sudden cardiac death and hydrops fetalis are often due to complete heart block. However, no pacing modality exists for intrauterine application for fetal bradycardia. A prototype lead for a novel fetal pacemaker has been developed and used in a direct pacing model. It has been demonstrated that the lead can be safely and successfully deployed using a hypochondriac and transdiaphragmatic or subxiphoid approach. Pacing with ventricular capture was evident with the widening of QRS duration from50.2 ± 9.8to95.1 ± 12.8 ms (P = 0.0001). Further studies by echocardiogram revealed an increase in the pulse with pacing, confirming pacing. This study documents proof-of-concept for closed thorax over-the-wire deployment of a novel lead design applicable to fetal pacing. By combining the lead design with microcircuitry and a small power source, it is possible to create a monolithic fetal pacemaker system capable of being deployed in utero. (PACE 2003; 26[Pt. I]:805,811) [source] Applying a test system for discriminating fetal from maternal cellsPRENATAL DIAGNOSIS, Issue 8 2003nar Bayrak-Toydemir Abstract Objective The objectives of this study were to enhance and apply a simple system capable of testing the capacity of putative, gender-independent fetal cell markers, individually and in combination, to discriminate between fetal and maternal cells. Methods Chorionic villi tissue obtained from 25 male pregnancies at 10 to 12 weeks' gestation served as the experimental group. Following removal of villi pieces for clinical use, unattached cells were collected by centrifugation of the CVS fluid, fixed in the tube, and used as a source of mixed fetal and maternal cells. Blood obtained from a fetus at 13 weeks' gestation served as a positive control. Peripheral blood from two adult males served as negative controls. Antibodies to three possible fetal markers were tested using immunohistochemical techniques: anti-Flk-1, anti-epsilon globin, and anti-CD71. Each antibody was used alone and in combination in conjunction with fluorescent in situ hybridization (FISH) of X and Y chromosomes to confirm that positively stained cells were in fact fetal in origin. Results On CVS samples, the average predictive value for anti-Flk-1 was 35.8%, 76.2% for anti-CD71, and 90.5% for anti-epsilon. The combination of anti-epsilon and anti-CD71 antibodies identifying a fetal cell was 87.2% and the combined use of single and double antibodies gave a value of 82.7%. The combination of anti-epsilon globin and anti-CD71 increased the sensitivity of identifying pure fetal blood cells from 63%, for anti-epsilon alone, and 67%, for anti-CD71 alone, to 86%. Conclusion Although anti-Flk-1 has been reported to be a successful marker of fetal cells, the results in this test system did not support this finding. This work supports the use of CVS washings containing both fetal and maternal cells as a viable test system for assessing antigenic markers. The combination of anti-CD71 and anti-epsilon as fetal identifiers may increase the chances of identifying a fetal cell without compromising the predictive value. Copyright © 2003 John Wiley & Sons, Ltd. [source] A comprehensive dictionary of protein accession codes for complete protein accession identifier alias resolvingPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 15 2006Andreas M. Boehm Abstract In mass spectrometry-based proteomics, protein identification results usually consist of peptide sequences and database-dependent accession identifiers of the matching proteins. Often certain annotations are only available in particular databases that in turn must be queried by a certain identifier. In order to simplify and unify the tracing of identified proteins back to their original annotation information, a system capable of set-oriented mapping the different accession identifiers of proteins derived from multiple sequence database sources has been developed. This allows unification of the access to protein information and tracing to other online resources providing additional information as well as resolving cross-references of protein identifications. The interface of seqDB is available via http://www.protein-ms.de following the link to seqDB. [source] RTS2: Lessons learned from a widely distributed telescope networkASTRONOMISCHE NACHRICHTEN, Issue 3 2008P. Kubánek Abstract RTS2 (Remote Telescope System 2) is a highly modular open source telescope and observatory management software package. It evolved from RTS, which was developed in Python to control a telescope aimed at observing optical transients of , ray burts. The development of a network system capable of operating robotic telescopes is both difficult and complicated. Along with continued software development one must be concerned with maintaining operations and obtaining results. This is a review of experiences gained building a network of robotic telescopes. It focuses on describing which issues are important during development of the robotic observatory software and requirements for future development of the RTS2 package. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Echtzeit-Röntgenuntersuchungen an duktilen stabförmigen Holzverbindungen bei dynamischer BeanspruchungBAUTECHNIK, Issue 10 2008Jörg Wehsener Dipl.-Ing. Der Beitrag beschreibt die Möglichkeiten von Röntgenuntersuchungen an stabförmigen Holzverbindungsmitteln im beanspruchten Bauteil. Trotz verschiedenartiger Untersuchungsmethoden ist die Bestimmung des tatsächlichen Verhaltens von metallischen Verbindungsmitteln im Holz während der Belastung nicht ausreichend gelöst. Mit Hilfe verschiedener mathematischer Ansätze und der Einbeziehung von Materialkennwerten ist die Modellierung von Holzverbindungen möglich. Die Nutzung von Röntgenstrahlen unter Echtzeitwiedergabe ermöglicht es, das Verformungsverhalten von metallischen Verbindungsmitteln während der Lasteinleitung zu beobachten. Ziel der Versuche war die Bestimmung des Verformungsverhaltens einer Stabdübelverbindung in Echtzeit unter quasistatischer und dynamischer Belastung. Mit der Echtzeit-radio-graphischen Messung wurden Versuche am Einzelstabdübel und einer Dübelgruppe durchgeführt. Die beim Versuch genutzte Anlage besteht aus einer mobilen Röntgenröhre und einem Detektor, sowie der dazugehörigen digitalen Bildverarbeitung. Bei maximaler Geschwindigkeit von 30 Bildern in der Sekunde wird eine Grenzwertauflösung von 1,97 lp/mm erreicht. Die Pixelteilung ist mit 127 ,m2 durch das Empfängermodul vorgegeben [10]. In Abhängigkeit der gewählten Parameter konnte die Verschiebung um einen Bildpunkt (0,21 mm) verifiziert werden. Eine Überprüfung der gemessenen Verformungen der Stabdübel erfolgte mit Hilfe von direkt aufgebrachten Dehnmessstreifen. Real time radioscopy investigations on ductile dowel-type fastener under dynamic load. This article discusses an application of real-time radioscopy in the investigation of dynamically loaded connections. Real-time radioscopy is especially suitable for connections of wood structures due to differences in density that are required for a radiographic image. With a real-time system, one can observe deformations of fasteners inside the investigated specimen. Theoretically, deformations can be quantified using image-processing techniques. The evaluation of deformations is, however, relatively complex due to the dimensionality of the problem where a 3-dimenional object is collapsed into its 2-D projection. A radiographic system capable of 30Hz frame acquisition frequency was used to study monotonically and cyclically loaded spliced and beam-to-column connections and an image-processing technique was used to estimate strains and study failure modes of the fasteners. [source] Weight loss predicts mortality after recurrent oral cavity and oropharyngeal carcinomas,CANCER, Issue 3 2002Thao V. Nguyen B.S.E. Abstract BACKGROUND The prognosis of patients with recurrent tumors of the head and neck generally is considered poor. Better prediction of outcomes can help physicians counsel patients about the merits of additional treatment. The TNM system, which was created for patients with primary tumors, may not provide optimal information. Anatomic staging systems traditionally have ignored symptom-based variables, such as weight loss, despite their known prognostic value. The objectives of this study were 1) to measure the prognostic impact of weight loss, 2) to evaluate the prognostic value of the TNM staging system, and 3) to create a practical staging system capable of predicting survival after patients develop recurrent tumors of the oral cavity and oropharynx. METHODS A retrospective chart review was used to identify an inception cohort of patients seeking treatment for recurrent, persistent, and second primary tumors of the oral cavity and oropharynx at the University of Washington. The primary outcome variable was 1-year survival. RESULTS The 1-year survival rate for the cohort (n = 97 patients) was 38%, with a median survival of 0.7 years. Multivariate analysis (Cox regression) identified weight loss, previous radiation to the head and neck, and TNM stage of the recurrent tumor as factors that had a substantial impact on mortality. A second multivariate technique called conjunctive consolidation was used to determine the relative quantitative impact of each variable on survival and to develop a clinical staging system. Weight loss and previous radiation had the greatest influence, and the use of just these two variables resulted in a three-tiered staging system with 1-year survival rates of 62% (16 of 26 patients), 44% (18 of 41 patients), and 10% (3 of 30 patients). In contrast, the TNM staging system produced survival rates of 60% (patients with Stage I disease), 67% (patients with Stage II disease), 32% (patients with Stage III disease), and 32% (patients with Stage IV disease). CONCLUSIONS The authors found substantial variation in survival after patients developed recurrent tumors of the oral cavity and oropharynx. Two readily available clinical variables,weight loss and previous radiation,were combined to create a clinically practical staging scheme with more prognostic power than the TNM staging system. Until molecular markers can reliably used be to predict outcomes, greater attention needs to be given to the utility of simple, inexpensive, and surprisingly powerful clinical variables. Cancer 2002;95:553,62. © 2002 American Cancer Society. DOI 10.1002/cncr.10711 [source] Discovery of New Biocatalysts for the Glycosylation of Terpenoid ScaffoldsCHEMISTRY - A EUROPEAN JOURNAL, Issue 22 2008Lorenzo Caputi Abstract The synthesis of terpenoid glycosides typically uses a chemical strategy since few biocatalysts have been identified that recognise these scaffolds. In this study, a platform of 107 recombinant glycosyltransferases (GTs), comprising the multigene family of small molecule GTs of Arabidopsis thaliana have been screened against a range of model terpenoid acceptors to identify those enzymes with high activity. Twenty-seven GTs are shown to glycosylate a diversity of mono-, sesqui- and diterpenes, such as geraniol, perillyl alcohol, artemisinic acid and retinoic acid. Certain enzymes showing substantial sequence similarity recognise terpenoids containing a primary alcohol, irrespective of the linear or cyclical structure of the scaffold; other GTs glycosylate scaffolds containing secondary and tertiary alcohols; the carboxyl group of other terpenoids also represents a feature that is recognized by GTs previously known to form glucose esters with many different compounds. These data underpin the rapid prediction of potential biocatalysts from GT sequence information. To explore the potential of GTs as biocatalysts, their use for the production of terpenoid glycosides was investigated by using a microbial-based whole-cell biotransformation system capable of regenerating the cofactor, UDP-glucose. A high cell density fermentation system was shown to produce several hundred milligrams of a model terpenoid, geranyl-glucoside. The activities of the GTs are discussed in relation to their substrate recognition and their utility in biotransformations as a complement or alternative to chemical synthesis. [source] Programmable Multiple Pacing Configurations Help to Overcome High Left Ventricular Pacing Thresholds and Avoid Phrenic Nerve StimulationPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 12 2005OSNAT GUREVITZ Background: High left ventricular pacing (LVP) thresholds and phrenic nerve stimulation (PNS) are common problems with cardiac resynchronization (CRT). Newer systems capable of multiple LVP configurations may help overcome these problems without the need for reoperation. Methods: CRT systems capable of multiple LVP configurations (Guidant models H155 and H145) were implanted in 43 patients (study group). An additional 49 patients (control group) received CRT systems (Guidant, Medtronic, Biotronik, St. Jude Medical, various models) lacking this feature. Results: Overall, acute high (,2.5 V/0.5 ms) LVP thresholds were encountered in 13 (30%) of the study group, and 25 (50%) of control group patients (P = 0.03). PNS was encountered in 5 (12%) of the study group and 12 (24%) of control group patients (P = 0.13). All cases of high LVP thresholds and PNS in the study group were managed by switching to a different LVP configuration, while high thresholds remained in control group patients, and PNS was managed by replacing the lead. The CS lead was successfully placed in a lateral branch in 95% of study group, compared to only 77% of control group patients (P = 0.004). Conclusions: Multiple LVP configurations were clinically useful in a significant number of patients undergoing CRT system implantation by helping to overcome high LVP thresholds and PNS, and by providing more flexibility in placing the LV lead. [source] Megapixels, Millimetres and Microsieverts: Packaging Digital Photogrammetry for Emerging Industrial MarketsTHE PHOTOGRAMMETRIC RECORD, Issue 95 2000D. P. Chapman As the performance of megapixel digital imaging systems continues to improve, the rapid growth of high-end consumer markets drives prices ever lower. When such cameras are married with emerging, desktop "photogrammetric" software packages, the close range photogrammetric community is faced with many new challenges and opportunities. The dramatic changes in the technological arena are matched by a rapidly changing business environment in which concepts such as "Partnering" and "Supply chain management" have become key themes. As organizations of all sizes seek to thrive within this new business landscape, there appears to be a willingness to think more flexibly about the client-supplier relationship and the sharing of risks and rewards. This, in turn, has encouraged the development of highly customized measurement solutions across a wide range of market sectors. In each of these solutions the emphasis is not on a generic photogrammetric product, but on a highly tailored system tightly coupled to existing workflows, and focused on the specific needs of the client. Such systems pose particular challenges to their designers, since they are frequently operated by users with relatively little photogrammetric background and yet must always meet the challenging requirement of producing an output which is "fit for purpose". Thus this paper hopes to show how novel megapixel imaging systems can be configured to deliver flexible measurement systems capable of millimetric level accuracy within the challenging engineering environments typical of the nuclear and process industries (hence the microsievert component of the title). [source] Innovation zur Bestimmung der Erdstoff-Geokunststoff-Wechselwirkung , Pullout-, Scher- und ReibungsversucheBAUTECHNIK, Issue 9 2004Taner Aydogmus Dipl.-Ing. Der Einsatz des ökonomischen und ökologischen Baumaterials "Geokunststoff" hat sich in den letzten Jahren in der Geotechnik für das Bauwesen, den Bergbau und den Umweltschutz stark verbreitet. In Form von Geotextilien, Geogittern, Geomembranen und verwandten Produkten ermöglichen sie technisch einfache, preisgünstige alternative Lösungsmöglichkeiten. Für die Berechnung der Standsicherheit von Konstruktionen mit Geokunststoffen, die für Bewehrungszwecke verwendet werden, ist die Ermittlung der "Reibungseigenschaften" in den Schichtgrenzen zwischen verschiedenen Geokunststoffen sowie zwischen Geokunststoffen und Erdstoffen unerläßlich. Zur Einschätzung der Hauptversagensmechanismen eines kunststoffbewehrten Erdkörpers werden üblicherweise Scher- und Reibungsversuche sowie nun auch verstärkt Pullout-Versuche durchgeführt. In diesem Beitrag wird ein neu entwickeltes und gebautes vollautomatisches Großrahmenschergerät mit integrierter Herausziehversuchseinrichtung vorgestellt, welches die Durchführung von vielfältigen innovativen Versuchen, mit leicht reproduzierbaren , den in-situ-Verhältnissen anpaßbaren , Randbedingungen, dem aktuellen Stand der Versuchstechnik entsprechend und nach den Vorgaben der neuen Normen (z. B. DIN 18137-3) ermöglicht. Innovation for the determination of the soil-geosynthetic interaction , pullout-, shear- and friction tests. The use of the economical and ecological construction material "geosynthetic" plays a rapidly increasing role in a variety of civil engineering, mining and environmental protection applications. Geosynthetics captured their own place as construction material due to their diversity and their specific characteristics. The applications of geosynthetics are many-sided. In the form of geotextiles, geogrids, geomembranes and related products, they make technically simple and low-priced alternative solution concepts possible. For the stability analysis of geosynthetic constructions knowledge of the friction behaviour in the geosynthetic interfaces is essential. For the assessment of the main failure mechanisms of a geosynthetic reinforced construction shear- and friction tests are usually performed as well as now also Pullout tests. In the following, a novel experimental apparatus for the examination of the interaction behaviour of soil-geosynthetic compound systems capable of performing both pullout and direct shear tests is described. In comparison with known geosynthetic testing practice, the novel testing apparatus offers the special advantage that a wide range of innovative shear and pullout test procedures can be carried out in the same device with negligible influence of test device configurations on friction test results. [source] Chromate Reduction in Shewanellaoneidensis MR-1 Is an Inducible Process Associated with Anaerobic GrowthBIOTECHNOLOGY PROGRESS, Issue 2 2002Sridhar Viamajala Cr(VI) reduction was observed during tests with Shewanella oneidensis MR-1 (previously named S. putrefaciens MR-1) while being grown with nitrate or fumarate as electron acceptor and lactate as electron donor. From the onset of anoxic growth on fumarate, we measured a gradual and progressive increase in the specific Cr(VI) reduction rate with incubation time until a maximum was reached at late exponential/early stationary phase. Under denitrifying conditions, the specific Cr(VI) reduction rate was inhibited by nitrite, which is produced during nitrate reduction. However, once nitrite was consumed, the specific reduction rate increased until a maximum was reached, again during the late exponential/early stationary phase. Thus, under both fumarate- and nitrate-reducing conditions, an increase in the specific Cr(VI) reduction rate was observed as the microorganisms transition from oxic to anoxic growth conditions, presumably as a result of induction of enzyme systems capable of reducing Cr(VI). Although Cr(VI) reduction has been studied in MR-1 and in other facultative bacteria under both oxic and anoxic conditions, a transition in specific reduction rates based on physiological conditions during growth is a novel finding. Such physiological responses provide information required for optimizing the operation of in situ systems for remediating groundwater contaminated with heavy metals and radionuclides, especially those that are characterized by temporal variations in oxygen content. Moreover, such information may point the way to a better understanding of the cellular processes used by soil bacteria to accomplish Cr(VI) reduction. [source] Self-Assembly of Two-Component Gels: Stoichiometric Control and Component SelectionCHEMISTRY - A EUROPEAN JOURNAL, Issue 2 2009Andrew Abstract Two-component systems capable of self-assembling into soft gel-phase materials are of considerable interest due to their tunability and versatility. This paper investigates two-component gels based on a combination of a L -lysine-based dendron and a rigid diamine spacer (1,4-diaminobenzene or 1,4-diaminocyclohexane). The networked gelator was investigated using thermal measurements, circular dichroism, NMR spectroscopy and small angle neutron scattering (SANS) giving insight into the macroscopic properties, nanostructure and molecular-scale organisation. Surprisingly, all of these techniques confirmed that irrespective of the molar ratio of the components employed, the "solid-like" gel network always consisted of a 1:1 mixture of dendron/diamine. Additionally, the gel network was able to tolerate a significant excess of diamine in the "liquid-like" phase before being disrupted. In the light of this observation, we investigated the ability of the gel network structure to evolve from mixtures of different aromatic diamines present in excess. We found that these two-component gels assembled in a component-selective manner, with the dendron preferentially recognising 1,4 - diaminobenzene (>70,%), when similar competitor diamines (1,2- and 1,3-diaminobenzene) are present. Furthermore, NMR relaxation measurements demonstrated that the gel based on 1,4-diaminobenzene was better able to form a selective ternary complex with pyrene than the gel based on 1,4-diaminocyclohexane, indicative of controlled and selective ,,, interactions within a three-component assembly. As such, the results in this paper demonstrate how component selection processes in two-component gel systems can control hierarchical self-assembly. [source] Comparative performances of selected chiral HPLC, SFC, and CE systems with a chemically diverse sample setCHIRALITY, Issue S1 2003Phil Borman Abstract Pharmaceutical companies have a continuous need to resolve new racemates. Analysis may be required in aqueous and nonaqueous media, or in the presence of several different sets of potentially interfering compounds. There is often a preparative requirement. For these reasons analysts may require a number of different separation systems capable of resolving a given pair of enantiomers. We wished to improve upon existing approaches that address this situation and undertook a program of work to screen over 100 racemates, selected for their chemical diversity, on over 100 different chiral HPLC, SFC, and CE systems. Here we report results of this comparison and illustrate the use of rapid gradient screening as a valuable tool for chiral method development. Chirality 15:S1,S12, 2003. © 2003 Wiley-Liss, Inc. 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