14,449 research outputs found
Schottky nanocontacts on ZnO nanorod arrays
We report on fabrication and electrical characteristics of ZnO nanorod Schottky diode arrays. High quality ZnO nanorods were grown for the fabrication of the Schottky diodes using noncatalytic metalorganic vapor phase epitaxy and Au was evaporated on the tips of the vertically well-aligned ZnO nanorods. I-V characteristics of both bare ZnO and Au/ZnO heterostructure nanorod arrays were measured using current-sensing atomic force microscopy. Although both nanorods exhibited nonlinear and asymmetric I-V characteristic curves, Au/ZnO heterostructure nanorods demonstrated much improved electrical characteristics: the reverse-bias breakdown voltage was improved from -3 to -8 V by capping a Au layer on the nanorod tips. The origin of the enhanced electrical characteristics for the heterostructure nanorods is suggested. (C) 2003 American Institute of Physics.X11326sciescopu
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KWM: Knowledge-based Workflow Model for agile organization
The workflow management system (WFMS) in an agile organization should be highly adaptable to the frequent organizational changes. To increase the adaptability of contemporary WFMSs, a mechanism for managing changes within the organizational structure and changes in business rules needs to be reinforced. In this paper, a knowledge-based approach for workflow modeling is proposed, in which a workflow is defined as a set of business rules. Knowledge on the organizational structure and special workflow, such as role/actor mappings and complex routing rules, can be explicitly modeled in KWM (Knowledge-based Workflow Model).
Using knowledge representation scheme and dependency management facility, a change propagation mechanism is provided to adapt to the frequent changes in the organizational structure, business rules, and procedures
Prediction of protein-protein interaction types using association rule based classification
This article has been made available through the Brunel Open Access Publishing Fund - Copyright @ 2009 Park et alBackground: Protein-protein interactions (PPI) can be classified according to their characteristics into, for example obligate or transient interactions. The identification and characterization of these PPI types may help in the functional annotation of new protein complexes and in the prediction of protein interaction partners by knowledge driven approaches. Results: This work addresses pattern discovery of the interaction sites for four different interaction types to characterize and uses them for the prediction of PPI types employing Association Rule Based Classification (ARBC) which includes association rule generation and posterior classification. We incorporated domain information from protein complexes in SCOP proteins and identified 354 domain-interaction sites. 14 interface properties were calculated from amino acid and secondary structure composition and then used to generate a set of association rules characterizing these domain-interaction sites employing the APRIORI algorithm. Our results regarding the classification of PPI types based on a set of discovered association rules shows that the discriminative ability of association rules can significantly impact on the prediction power of classification models. We also showed that the accuracy of the classification can be improved through the use of structural domain information and also the use of secondary structure content. Conclusion: The advantage of our approach is that we can extract biologically significant information from the interpretation of the discovered association rules in terms of understandability and interpretability of rules. A web application based on our method can be found at http://bioinfo.ssu.ac.kr/~shpark/picasso/SHP was supported by the Korea Research Foundation Grant funded by the Korean Government(KRF-2005-214-E00050). JAR has been
supported by the Programme Alβan, the European Union Programme of High level Scholarships for Latin America, scholarship E04D034854CL. SK was supported by Soongsil University Research Fund
Liposome-based drug delivery in breast cancer treatment
Drug delivery systems can in principle provide enhanced efficacy and/or reduced toxicity for anticancer agents. Long circulating macromolecular carriers such as liposomes can exploit the 'enhanced permeability and retention' effect for preferential extravasation from tumor vessels. Liposomal anthracyclines have achieved highly efficient drug encapsulation, resulting in significant anticancer activity with reduced cardiotoxicity, and include versions with greatly prolonged circulation such as liposomal daunorubicin and pegylated liposomal doxorubicin. Pegylated liposomal doxorubucin has shown substantial efficacy in breast cancer treatment both as monotherapy and in combination with other chemotherapeutics. Additional liposome constructs are being developed for the delivery of other drugs. The next generation of delivery systems will include true molecular targeting; immunoliposomes and other ligand-directed constructs represent an integration of biological components capable of tumor recognition with delivery technologies
Formulation and Pharmacokinetic Evaluation of Controlled-Release Oxybutynin Tablets in Dogs
Purpose: To develop and optimize controlled-release (CR) oxybutynin chloride matrix tablets.Methods: Oxybutynin CR tablets were prepared by embedding drug-containing granules into a hydrogel matrix of hydroxypropyl methylcellulose (HPMC). A coating layer was then applied with a mixture of HPMC, ethylcellulose, shellac, and HPMC phthalate. The effect of several formulation variables on in vitro drug release was studied; furthermore, the drug release kinetics of the optimized formulation was evaluated. The in vivo pharmacokinetics of the optimized formulation was compared with those of commercial immediate-release and CR tablets in dogs.Results: The core tablets exhibited extended release consisting of drug release from the embedded granules through the erodible hydrogel matrix. Release rate was controlled by the amounts of swellingcontrol agent and hydrogel used. The optimized formulation followed zero-order release up to 24 h after an initial lag time. Maximum plasma drug concentration for the optimized and commercial CR tablets was 5.90 ± 1.42 and 6.47 ± 3.73 ng/mL, respectively, while the area under the plasma concentration– time curve was 101.40 ± 51.41 and 112.68 ± 65.89 ng∙h/mL, respectively.Conclusion: The formulated oxybutynin CR tablets exhibit prolonged drug release, thus rendering it a potentially suitable once-daily oral formulation for improved patient compliance.Keywords: Oxybutynin, Matrix tablet, Hydrogel, Oral controlled-release, Zero-order release,Pharmacokinetic
More, More, More: Reducing Thrombosis in Acute Coronary Syndromes Beyond Dual Antiplatelet Therapy-Current Data and Future Directions.
© 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.Common to the pathogenesis of acute coronary syndromes (ACS) is the formation of arterial thrombus, which results from platelet activation and triggering of the coagulation cascade.1 To attenuate the risk of future thrombotic events, patients with ACS are treated with dual antiplatelet therapy (DAPT), namely, the combination of aspirin with a P2Y12 inhibitor, such as clopidogrel, ticagrelor, or prasugrel. Despite DAPT, some ≈10% of ACS patients experience recurrent major adverse cardiovascular events over the subsequent 30 days,2 driving the quest for more effective inhibition of thrombotic pathways. In this review, we provide an overview of studies to date and those ongoing that aim to deliver more effective combinations of antithrombotic agents to patients with recent ACS. We have chosen to confine the review to ACS patients without atrial fibrillation because those with atrial fibrillation have a clear indication for combination therapy that includes oral anticoagulation and should, we feel, be treated as a separate cohort. In this article, we discuss the limitations of the currently available clinical trial data and future directions, with suggestions for how practice might change to reduce the risk of coronary thrombosis in those at greatest risk, with minimal impact on bleeding.Peer reviewedFinal Published versio
Policy Regimes, Policy Shifts, and U.S. Business Cycles
Session - Monetary EconomicsUsing an estimated DSGE model that features monetary and fiscal policy interactions and allows for equilibrium indeterminacy, we find that a passive monetary and passive fiscal policy regime prevailed in the pre-Volcker period while an active monetary and passive fiscal policy regime prevailed post-Volcker. Since both monetary and fiscal policies were passive pre-Volcker, there was equilibrium indeterminacy that gave rise to self-fulfilling beliefs and resulted in substantially different transmission mechanisms of policy as compared to conventional models: unanticipated increases in interest rates increased inflation and output while unanticipated increases in lump-sum taxes decreased inflation and output. Unanticipated shifts in monetary and fiscal policies however, played no substantial role in explaining the variation of inflation and output at any horizon in either of the time periods. Pre-Volcker, in sharp contrast to post-Volcker, we find that a time-varying inflation target does not explain low-frequency movements in inflation. A combination of shocks account for the dynamics of output, inflation, and government debt, with the relative importance of a particular shock quite different in the two time-periods due to changes in the systematic responses of policy. Finally, in a counterfactual exercise, we show that had the monetary policy regime of the post-Volcker era been in place pre-Volcker, inflation volatility would have been lower by 34% and the rise of inflation in the 1970s would not have occurred.postprin
Inflation dynamics: the role of public debt and policy regimes
Session III-7: Macroeconomics IV - Policy Regimes and DSGE ModelsWe investigate the impact of a time-varying inflation target and changing monetary and fiscal policy stances on the dynamics of inflation in a DSGE model. Under an active monetary and passive fiscal policy regime, inflation closely follows the path of the inflation target and a stronger reaction of monetary policy to inflation decreases the equilibrium response of inflation to non-policy shocks. In sharp contrast, under an active fiscal and passive monetary policy regime, inflation moves in an opposite direction from the inflation target and a stronger reaction of monetary policy to inflation increases the equilibrium response of inflation to non-policy shocks. Moreover, a weaker response of fiscal policy to debt decreases the response of inflation to non-policy shocks. These results are due to variation in the value of public debt that lead to wealth effects on households. Finally, under a passive monetary and passive fiscal policy regime, because of equilibrium indeterminacy, theory provides no clear answer on the behavior of inflation. We characterize these results analytically in a simple model and numerically in a richer quantitative model.postprin
The emergence of a multiscalar growth regime and scalar tension: the politics of urban development in Songdo New City, South Korea
This study approaches the politics of urban development from within the framework of the emergence of a new multiscalar growth regime and the path dependence of the Korean developmental state. Through a case study of the Songdo New City development in South Korea, this study looks at how the scalar division of labor among various actors has interacted with the emergence of a multiscalar growth regime. We focus on the logic by which different scales of governmental and nongovernmental actors cooperate and, at the same time, compete with one another for authority over economic development. Our findings demonstrate, first, that the new regime resulted from the emergence of downward state rescaling to the local scale and of private business as a key actor. Second, the regime actors have been involved in scalar tensions and have constantly negotiated the scalar divisions of labor among them. This research provides a contextualized example of a spatiotemporal logic in which statehood has been transformed into a network
Optimal Monetary Policy in a Currency Union with Interest Rate Spreads
The Conference papers' website is located at http://dev3.cepr.org/meets/wkcn/1/1806/papers/default.htmPoster Session 1A Euro Area Business Cycle Network (EABCN) ConferenceWe study optimal monetary policy in a two-country currency union model with nominal and financial frictions. In addition to, and independent from, the standard transmission mechanism associated with sticky prices, financial frictions combined with asymmetric asset positions introduce a wealth redistribution role for monetary policy in our model. Financial frictions also lead to a spread between the deposit and borrowing interest rate and variation in the spread affects both aggregate variables, by affecting total spending, and relative (cross-country) variables, by redistributing wealth across countries. Moreover, the interactions between nominal and financial frictions amplify the effects of monetary policy; imply that a strict inflation targeting policy of setting union-wide inflation to zero is never optimal and that optimal policy never attains efficiency; and lead to a novel policy trade-o¤ for the central bank in stabilizing relative consumption versus the relative price gap (the deviation of relative prices from their efficient level). Finally, under optimal monetary policy, in response to an aggregate purely financial shock that causes an increase in the interest rate spread, the central bank strongly decreases the deposit rate, which reduces aggregate and distributional inefficiencies by mitigating the drop in output and inflation and the rise in relative consumption and prices. We also show that while a traditional Taylor rule approximates optimal policy imperfectly, especially in response to the financial shock, a spread-adjusted Taylor rule performs better as it helps the real interest rate track the efficient rate of interest.postprin
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