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Improved Methodology (improved + methodology)
Selected AbstractsImproved synthesis of DOTA tetraamide ligands for lanthanide(III) ions: A tool for increasing the repertoire of potential PARACEST contrast agents for MRI and/or fluorescent sensorsCONTRAST MEDIA & MOLECULAR IMAGING, Issue 3 2010Luis M. De León-Rodríguez Abstract The synthesis of new DOTA tetraamide (DOTAMR4) compounds is of great interest given their application in the formation of Ln(III) complexes as potential PARACEST contrast agents in MRI or fluorescent molecular probes. In this context amino acid and peptide DOTAMR4 derivatives are particularly attractive since the amino-acid and/or peptide moiety can show responsive properties dependent on a given stimuli which might translate to changes in water exchange rates of the corresponding Ln(III) complex. Current synthesis of DOTAMR4 derivatives is typically carried out by reacting haloacetamide intermediates with cyclen. However, this method fails to generate the tetra-substituted products when bulky substituents are present in the haloacetamide and in some cases this intermediate cannot be prepared by conventional acylation procedures limiting the number of DOTAMR4 compounds available for study. As a solution to these limitations, an improved methodology for the synthesis of DOTAMR4 by coupling DOTA to an appropriate amine containing reagent (i.e. protected amino-acids with the , -amino group free) is presented in this work. Several DOTAMR4 derivatives which are difficult or impossible to prepare with the traditional methodologies were easily obtained starting with DOTA. A new protocol was derived using this methodology for the solution-phase synthesis of DOTA peptide derivatives. With this methodology, many other DOTAMR4 peptide and non-peptide derivatives have been prepared in our laboratories with several of these new compounds showing interesting properties for molecular imaging. Copyright © 2010 John Wiley & Sons, Ltd. [source] Post-earthquake bridge repair cost and repair time estimation methodologyEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 3 2010Kevin R. Mackie Abstract While structural engineers have traditionally focused on individual components (bridges, for example) of transportation networks for design, retrofit, and analysis, it has become increasingly apparent that the economic costs to society after extreme earthquake events are caused at least as much from indirect costs as direct costs due to individual structures. This paper describes an improved methodology for developing probabilistic estimates of repair costs and repair times that can be used for evaluating the performance of new bridge design options and existing bridges in preparation for the next major earthquake. The proposed approach in this paper is an improvement on previous bridge loss modeling studies,it is based on the local linearization of the dependence between repair quantities and damage states so that the resulting model follows a linear relationship between damage states and repair points. The methodology uses the concept of performance groups (PGs) that account for damage and repair of individual bridge components and subassemblies. The method is validated using two simple examples that compare the proposed method to simulation and previous methods based on loss models using a power,law relationship between repair quantities and damage. In addition, an illustration of the method is provided for a complete study on the performance of a common five-span overpass bridge structure in California. Intensity-dependent repair cost ratios (RCRs) and repair times are calculated using the proposed approach, as well as plots that show the disaggregation of repair cost by repair quantity and by PG. This provides the decision maker with a higher fidelity of data when evaluating the contribution of different bridge components to the performance of the bridge system, where performance is evaluated in terms of repair costs and repair times rather than traditional engineering quantities such as displacements and stresses. Copyright © 2009 John Wiley & Sons, Ltd. [source] Consulting the source code: prospects for gene-based medical diagnosticsJOURNAL OF INTERNAL MEDICINE, Issue S741 2001U. Landegren Abstract. Landegren U (Rudbeck Laboratory, Uppsala, Sweden) Gene-based diagnostics (Internal Medicine in the 21st Century). J Intern Med 2000; 248: 271,276. Gene-based diagnostics has been slow to enter medical routine practice in a grand way, but it is now spurred on by three important developments: the total genetic informational content of humans and most of our pathogens is rapidly becoming available; a very large number of genetic factors of diagnostic value in disease are being identified; and such factors include the identity of genes frequently targeted by mutations in specific diseases, common DNA sequence variants associated with disease or responses to therapy, and copy number alterations at the level of DNA or RNA that are characteristic of specific diseases. Finally, improved methodology for genetic analysis now brings all of these genetic factors within reach in clinical practice. The increasing opportunities for genetic diagnostics may gradually influence views on health and normality, and on the genetic plasticity of human beings, provoking discussions about some of the central attributes of genetics. [source] An improved experimental and regression methodology for sorption isothermsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 2 2005Elisabeth J Quirijns Abstract Sorption isotherms of corn and starch cylinders with immobilised catalase are experimentally determined at different temperatures for use in drying models in optimal control studies. This application of the sorption isotherm requires an accurate prediction of the sorption data at different temperatures for the low water activity range. The GAB equation is used for the prediction of the sorption isotherms. Two major problems are encountered by employing standard procedures, ie prediction of sorption at aw < 0.11 and sensitivity of the GAB parameters to the applied data range. An improved methodology is developed, consisting of extending the standard experimental procedure with additional data points in the low water activity range and changing the criterion in the regression procedure in the sum of squares, which is weighed by the variance of the experimental data. The new methodology leads to accurate, consistent and physically relevant parameters of the GAB equation, which are independent of the applied data range in the regression analysis and which result in accurate predictions of the sorption behaviour at low water activity. The sorption data at different temperatures at low water activity can be predicted in the best way with parameters obtained after direct regression based on weighed SSQ. Copyright © 2004 Society of Chemical Industry [source] Are apes inequity averse?AMERICAN JOURNAL OF PRIMATOLOGY, Issue 2 2009New data on the token-exchange paradigm Abstract Recent studies have produced mixed evidence about inequity aversion in nonhuman primates. Brosnan et al. [Proceedings of the Royal Society of London. Series B. Biological Sciences 272:253,258, 2005] found inequity aversion in chimpanzees and argued that effort is crucial, if subjects are to evaluate how they are rewarded in comparison to a competitor for an identical performance. In this study we investigated inequity aversion with chimpanzees, bonobos and orangutans, using the method of Brosnan et al. [Proceedings of the Royal Society of London. Series B. Biological Sciences 272:253,258, 2005] after introducing some methodological improvements. Subjects always received a less-preferred food in exchange for a token, whereas the competitor received either the same type of food for their token (equity) or a more favored food for it (inequity). Apes did not refuse more of the less-preferred food when a competitor had received the more favored food. Thus, with an improved methodology we failed to reproduce the findings of Brosnan et al. [Proceedings of the Royal Society of London. Series B. Biological Sciences 272:253,258, 2005] that apes show inequity aversion. Am. J. Primatol. 71:175,181, 2009. © 2008 Wiley-Liss, Inc. [source] The assimilation of SSM/I and TMI rainfall rates in the ECMWF 4D-Var systemTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 606 2005Jean-françois Mahfouf Abstract A recent version of the European Centre for Medium-Range Weather Forecasts four-dimensional variational (4D-Var) assimilation system (40 km horizontal resolution with a 12-hour window) is used to examine the comparative impact of including satellite-derived rainfall rates from SSM/I and TMI radiometers within the tropics. The methodology is similar to the one proposed by Marécal and Mahfouf (2002) where Total Column Water Vapour (TCWV) retrievals in rainy areas from a simplified 1D-Var assimilation are introduced in the 4D-Var system. An improved methodology for the estimation of rain rate retrieval errors proposed by Bauer et al. (2002) is used. Three one-month experiments are undertaken: a control run (no rain rate assimilation), a TMI run (assimilation of TMI-derived rain rates) and a SSM/I run (assimilation of SSM/I-derived rain rates). The corrections of TCWV in rainy areas introduced in the 4D-Var are very similar between SSM/I and TMI because they are dominated by the ,no rain' information. The impact of TMI and SSM/I assimilations is positive on forecast scores, both in the extratropics and in the tropics. Results from the SSM/I run show a larger positive impact which tends to demonstrate the benefit of the increased number of data from the SSM/I with respect to TMI. Copyright © 2005 Royal Meteorological Society. [source] Validation of crystallographic models containing TLS or other descriptions of anisotropyACTA CRYSTALLOGRAPHICA SECTION D, Issue 8 2010Frank Zucker The use of TLS (translation/libration/screw) models to describe anisotropic displacement of atoms within a protein crystal structure has become increasingly common. These models may be used purely as an improved methodology for crystallographic refinement or as the basis for analyzing inter-domain and other large-scale motions implied by the crystal structure. In either case it is desirable to validate that the crystallographic model, including the TLS description of anisotropy, conforms to our best understanding of protein structures and their modes of flexibility. A set of validation tests has been implemented that can be integrated into ongoing crystallographic refinement or run afterwards to evaluate a previously refined structure. In either case validation can serve to increase confidence that the model is correct, to highlight aspects of the model that may be improved or to strengthen the evidence supporting specific modes of flexibility inferred from the refined TLS model. Automated validation checks have been added to the PARVATI and TLSMD web servers and incorporated into the CCP4i user interface. [source] An improved methodology of the modern analogues technique for palaeoclimate reconstruction in arid and semi-arid regionsBOREAS, Issue 1 2010WENYING JIANG Jiang, W., Guiot, J., Chu, G., Wu, H., Yuan, B., Hatté, C. & Guo, Z. 2009: An improved methodology of the modern analogues technique for palaeoclimate reconstruction in arid and semi-arid regions. Boreas, 10.1111/j.1502-3885.2009.00115.x. ISSN 0300-9483. This study presents an improved method of the plant functional type modern analogues technique (PFT-MAT) in which environmental proxies and a moisture index (,, i.e. ratio of actual evapotranspiration to potential evapotranspiration) are used to constrain the selection of modern analogues. The method is tested using high-resolution, precisely dated palaeorecords (pollen, Pediastrum and ,18O of authigenic carbonate) from Lake Bayanchagan, northern China. The unconstrained and constrained PFT-MAT produces general agreement for Holocene climate changes, with a wet period between 11 000 and 5500 cal. yr BP and a warm interval between 11 000 and 8000 cal. yr BP. However, there are significant differences in the details of their reconstruction. The constrained PFT-MAT generally yields smaller error bars for the reconstructed climate parameters than the unconstrained PFT-MAT. In addition, three prominent climatic events are identified from the constrained reconstructions; namely, a cold event around 8400 cal. yr BP and two warm events around 6000 and 2000 cal. yr BP, which is consistent with other regional palaeoclimatic records. Our data show that changes in tree components correlate well with , variations during the entire Holocene, with the highest tree components and highest , values between 8000 and 5500 cal. yr BP, indicating the dominant role of , in the growth of trees in northern China rather than single temperature or precipitation. The improved PFT-MAT is therefore an efficient method for quantitative reconstructions of palaeoclimate in arid and semi-arid regions. [source] | ||||||||||||||||