Home About us Contact
|
Home About us Contact | ||
|
|
||
General Strategy (general + strategy)
Selected AbstractsA General Strategy to Disperse and Functionalize Carbon Nanotubes Using Conjugated Block CopolymersADVANCED FUNCTIONAL MATERIALS, Issue 3 2009Jianhua Zou Abstract A general strategy to disperse and functionalize pristine carbon nanotubes in a single-step process is developed using conjugated block copolymers. The conjugated block copolymer contains two blocks: a conjugated polymer block of poly(3-hexylthiophene), and a functional non-conjugated block with tunable composition. When the pristine carbon nanotubes are sonicated with the conjugated block copolymers, the poly(3-hexylthiophene) blocks bind to the surface of de-bundled carbon nanotubes through non-covalent ,,, interactions, stabilizing the carbon nanotube dispersion, while the functional blocks locate at the outer surface of carbon nanotubes, rendering the carbon nanotubes with desired functionality. In this paper, conjugated block copolymers of poly(3-hexylthiophene)- b -poly(methyl methacrylate), poly(3-hexylthiophene)- b -poly(acrylic acid), and poly(3-hexylthiophene)- b -poly(poly(ethylene glycol) acrylate) are used to demonstrate this general strategy. [source] Rhodium-Catalyzed Enantioselective Desymmetrization of meso-3,5-Dimethyl Glutaric Anhydride: A General Strategy to syn-Deoxypolypropionate Synthons.CHEMINFORM, Issue 50 2007Matthew J. Cook 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, please click on HTML or PDF. [source] Thiazolium-Catalyzed Additions of Acylsilanes: A General Strategy for Acyl Anion Addition Reactions.CHEMINFORM, Issue 48 2006Anita E. Mattson 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, please click on HTML or PDF. [source] Highly Diastereoselective Alkylation of Vicinal Dianions of Chiral Succinic Acid Derivatives: A New General Strategy to (R)-,-Arylmethl-,-butyrolactones.CHEMINFORM, Issue 36 2004Manat Pohmakotr Abstract For Abstract see ChemInform Abstract in Full Text. [source] General Strategy for a Large-Scale Fabric with Branched Nanofiber,Nanorod Hierarchical Heterostructure: Controllable Synthesis and ApplicationsCHEMISTRY - A EUROPEAN JOURNAL, Issue 37 2010Meng Shang Abstract The preparation and characterization of a branched nanofiber,nanorod hierarchical heterostructure fabric (TiO2/NiO, TiO2/ZnO, and TiO2/SnO2) are described. The nanomaterial was synthesized on a large scale by an inexpensive, generalizable, facile, and controllable approach by combining the electrospinning technique with a hydrothermal method. The controllable formation process and factors (assistance by hexamethylenetetramine and metal oxide nuclei) influencing the morphology of the branched hierarchical heterostructure are discussed. In addition, photocurrent and photocatalytic studies suggest that the branched hierarchical heterostructure fabric shows higher mobility of charge carriers and enhanced photocatalytic activity relative to a bare TiO2 nanofibrous mat and other heterostructures under irradiation by light. This work demonstrates the possibility of growing branched heterostructure fabrics of various uniform, one-dimensional, functional metal oxide nanorods on a TiO2 nanofibrous mat, which has a tunable morphology by changing the precursor. The study may open a new channel for building hierarchical heterostructure device fabrics with optical and catalytic properties, and allow the realization of a new class of nano-heterostructure devices. [source] Is there a downside to customizing care?JOURNAL OF EVALUATION IN CLINICAL PRACTICE, Issue 6 2009Implications of general, patient-specific treatment strategies Abstract Rationale, aims and objectives, The use of general clinical guidelines versus customization of patient care presents a dilemma for clinicians managing chronic illness. The objective of this project is to investigate the claim that the performance of customized strategies for the management of chronic illness depends on accurate patient categorization, and inaccurate categorization can lead to worse performance than that achievable using a general clinical guideline. Methods, This paper is based on an analysis of a basic utility model that differentiates between the use of general management strategies and customized strategies. Results, The analysis identifies necessary conditions for preferring general strategies to customized strategies as a trade-off between strategy performance and the probability of correct patient categorization. The analysis shows that customized treatment strategies developed under optimal conditions are not necessarily preferred. Conclusions, Results of the analysis have four implications regarding the design and use of clinical guidelines and customization of care: (i) the balance between the applications of more general strategies versus customization depends on the specificity and accuracy of the strategies; (ii) adoption of clinical guidelines may be stifled as the complexity of guidelines increases to account for growing evidence; (iii) clinical inertia (i.e. the failure to intensify an indicated treatment) can be a rational response to strategy specificity and the probability of misapplication; and, (iv) current clinical guidelines and other decision-support tools may be improved if they accommodate the need for customization of strategies for some patients while providing support for proper categorization of patients. [source] The Language of "Circule":MEDICAL ANTHROPOLOGY QUARTERLY, Issue 3 2010Discursive Construction of False Referral in Iranian Teaching Hospitals This article explores the practice of false patient out-referral by medical students in Iranian teaching hospital emergency departments. Drawing on participant-observations and interviews during eight months in six hospitals in Tehran, we investigate how discourse is appropriated to construct and legitimate out-referrals through four general strategies of sympathy, mystification, intimidation, and procrastination. Based on a critical approach to false out-referral discourse, we revisit the medical and educational functioning of teaching hospitals in Iran: Focusing on medical students involved in false out-referrals, their discursive reproduction of deception is examined along with their legitimate challenges to institutional structures. Moreover, focusing on the institution of hospital, institutional corruption is discussed along with the problematic of covert cultural defiance faced by a modernist organizational construct in a nonmainstream cultural context. Finally, we argue that the discourse of false out-referral calls for more profound public awareness in dealing with health institutions. [source] Climatic variability and the evolution of insect freeze toleranceBIOLOGICAL REVIEWS, Issue 2 2003BRENT J. SINCLAIR ABSTRACT Insects may survive subzero temperatures by two general strategies: Freeze-tolerant insects withstand the formation of internal ice, while freeze-avoiding insects die upon freezing. While it is widely recognized that these represent alternative strategies to survive low temperatures, and mechanistic understanding of the physical and molecular process of cold tolerance are becoming well elucidated, the reasons why one strategy or the other is adopted remain unclear. Freeze avoidance is clearly basal within the arthropod lineages, and it seems that freeze tolerance has evolved convergently at least six times among the insects (in the Blattaria, Orthoptera, Coleoptera, Hymenoptera, Diptera and Lepidoptera). Of the pterygote insect species whose cold-tolerance strategy has been reported in the literature, 29% (69 of 241 species studied) of those in the Northern Hemisphere, whereas 85%(11 of 13 species) in the Southern Hemisphere exhibit freeze tolerance. A randomization test indicates that this predominance of freeze tolerance in the Southern Hemisphere is too great to be due to chance, and there is no evidence of a recent publication bias in favour of new reports of freeze-tolerant species. We conclude from this that the specific nature of cold insect habitats in the Southern Hemisphere, which are characterized by oceanic influence and climate variability must lead to strong selection in favour of freeze tolerance in this hemisphere. We envisage two main scenarios where it would prove advantageous for insects to be freeze tolerant. In the first, characteristic of cold continental habitats of the Northern Hemisphere, freeze tolerance allows insects to survive very low temperatures for long periods of time, and to avoid desiccation. These responses tend to be strongly seasonal, and insects in these habitats are only freeze tolerant for the overwintering period. By contrast, in mild and unpredictable environments, characteristic of habitats influenced by the Southern Ocean, freeze tolerance allows insects which habitually have ice nucleators in their guts to survive summer cold snaps, and to take advantage of mild winter periods without the need for extensive seasonal cold hardening. Thus, we conclude that the climates of the two hemispheres have led to the parallel evolution of freeze tolerance for very different reasons, and that this hemispheric difference is symptomatic of many wide-scale disparities in Northern and Southern ecological processes. [source] Design of Gold Nanoparticle-Based Colorimetric Biosensing AssaysCHEMBIOCHEM, Issue 15 2008Weian Zhao Abstract Gold nanoparticle (AuNP)-based colorimetric biosensing assays have recently attracted considerable attention in diagnostic applications due to their simplicity and versatility. This Minireview summarizes recent advances in this field and attempts to provide general guidance on how to design such assays. The key to the AuNP-based colorimetric sensing platform is the control of colloidal AuNP dispersion and aggregation stages by using biological processes (or analytes) of interest. The ability to balance interparticle attractive and repulsive forces, which determine whether AuNPs are stabilized or aggregated and, consequently, the color of the solution, is central in the design of such systems. AuNP aggregation in these assays can be induced by an "interparticle-crosslinking" mechanism in which the enthalpic benefits of interparticle bonding formation overcome interparticle repulsive forces. Alternatively, AuNP aggregation can be guided by the controlled loss of colloidal stability in a "noncrosslinking-aggregation" mechanism. In this case, as a consequence of changes in surface properties, the van der Waals attractive forces overcome interparticle repulsive forces. Using representative examples we illustrate the general strategies that are commonly used to control AuNP aggregation and dispersion in AuNP-based colorimetric assays. Understanding the factors that play important roles in such systems will not only provide guidance in designing AuNP-based colorimetric assays, but also facilitate research that exploits these principles in such areas as nanoassembly, biosciences and colloid and polymer sciences. [source] The Molecular Basis of Self-Assembly of Dendron,Rod,Coils into One-Dimensional NanostructuresCHEMISTRY - A EUROPEAN JOURNAL, Issue 28 2006Eugene R. Zubarev Prof. Abstract We describe here a comprehensive study of solution and solid-state properties of self-assembling triblock molecules composed of a hydrophilic dendron covalently linked to an aromatic rigid rod segment, which is in turn connected to a hydrophobic flexible coil. These dendron,rod,coil (DRC) molecules form well-defined supramolecular structures that possess a ribbonlike morphology as revealed by transmission-electron and atomic-force microscopy. In a large variety of aprotic solvents, the DRC ribbons create stable networks that form gels at concentrations as low as 0.2,% by weight DRC. The gels are thermally irreversible and do not melt at elevated temperatures, indicating high stability as a result of strong noncovalent interactions among DRC molecules. NMR experiments show that the strong interactions leading to aggregation involve mainly the dendron and rodlike blocks, whereas oligoisoprene coil segments remain solvated after gelation. Small-angle X-ray scattering (SAXS) profiles of different DRC molecules demonstrate an excellent correlation between the degree-of-order in the solid-state and the stability of gels. Studies on two series of analogous molecules suggest that self-assembly is very sensitive to subtle structural changes and requires the presence of at least four hydroxyl groups in the dendron, two biphenyl units in the rod, and a coil segment with a size comparable to that of the rodlike block. A detailed analysis of crystal structures of model compounds revealed the formation of stable one-dimensional structures that involve two types of noncovalent interactions, aromatic ,,, stacking and hydrogen bonding. Most importantly, the crystal structure of the rod,dendron compound shows that hydrogen bonding not only drives the formation of head-to-head cyclic structures, but also generates multiple linkages between them along the stacking direction. The cyclic structures are tetrameric in nature and stack into ribbonlike objects. We believe that DRC molecules utilize the same arrangement of hydrogen bonds and stacking of aromatic blocks observed in the crystals, explaining the exceptional stability of the nanostructures in extremely dilute solutions as well the thermal stability of the gels they form. This study provides mechanistic insights on self-assembly of triblock molecules, and unveils general strategies to create well-defined one-dimensional supramolecular objects. [source] Stereoselective Synthesis of the First Chatt-Type Bis(dinitrogen)-Molybdenum(0) Complex with a Tetraphosphane LigandEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 21 2008René Römer Abstract The first Chatt-type Mo0 dinitrogen complex with a tetraphosphane ligand has been prepared and characterized by NMR as well as infrared and Raman spectroscopy. Importantly, the employed reaction route allows the stereospecific synthesis of this complex as trans -[Mo(N2)2(meso -prP4)] (prP4 = a tetraphos ligand with a central propylene bridge). The stereoselectivity in the reaction course is induced by the oxido-iodido-molybdenum(IV) precursor [Mo(O)I(prP4)]+ which directs both phenyl groups of the bridging P atoms of prP4 into a meso configuration. The paper establishes a general strategy to synthesize mononuclear Mo0 dinitrogen and related molybdenum complexes with multidentate phosphane ligands which has not been possible to date. Moreover, the obtained molybdenum tetraphos N2 complex should exhibit a higher thermodynamic stability in the reactions of the Chatt cycle of synthetic nitrogen fixation than the conventional bis(diphos) complexes, due to the linkage of the two diphosphane units by an alkyl bridge. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Intramolecular Opening of ,-Lactams with Amines as a Strategy Toward Enzymatically or Photochemically Triggered Activation of Lactenediyne ProdrugsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 7 2003Luca Banfi Abstract In order to develop a general strategy for selective activation of designed enediyne prodrugs belonging to the "lactenediyne" family, we studied the scope of intramolecular transamidation of simple monocyclic ,-lactams bearing a tethered amine. The effect of substituents, of reaction media, and of the type of tether, on the rate of transamidation is disclosed. The possibility of triggering the transamidation event under mild conditions by the action of suitable enzymes or UV light was demonstrated on model monocyclic ,-lactams. Finally, the strategy of intramolecular opening of the ,-lactam leading to a larger seven-membered ring was employed on a lactenediyne, demonstrating that ring enlargement could unleash the reactivity of the enediyne moiety. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] A General Electrochemical Strategy for Synthesizing Charge-Transfer Complex Micro/NanowiresADVANCED FUNCTIONAL MATERIALS, Issue 8 2010Liang Ren Abstract Universal strategies for synthesizing one-dimensional organic nanomaterials are of fundamental importance in the development of more flexible, cheaper and lighter electronics. Charge-transfer (CT) complexes, the major kind of organic conductors, are in the long-term attractive materials owing to their unique crystal structures and conductive properties. In this article, a general strategy for the synthesis of CT complex micro/nanowires based on the localized nanoelectrochemistry using tiny carbon nanotube (CNT) electrodes is presented. This strategy is successfully demonstrated over 12 typical CT complexes, and a general rule for the preparation of various kinds of CT complex micro/nanowires is summarized. The CT complex micro/nanowires thus synthesized have high aspect ratios and long lengths as compared with traditional macroscopic planar electrodes, originating from the one-dimensional structural feature with fewer or no defects and the ultrasmall surface area of the CNT. This work provides a more versatile material basis for the fundamental and application studies of low-dimensional organic conductor materials. [source] Generic Strategy of Preparing Fluorescent Conjugated-Polymer-Loaded Poly(DL -lactide- co -Glycolide) Nanoparticles for Targeted Cell ImagingADVANCED FUNCTIONAL MATERIALS, Issue 22 2009Kai Li Abstract A general strategy for the preparation of highly fluorescent poly(DL-lactide- co -glycolide) (PLGA) nanoparticles (NPs) loaded with conjugated polymers (CPs) is reported. The process involves encapsulation of organic-soluble CPs with PLGA using a modified solvent extraction/evaporation technique. The obtained NPs are stable in aqueous media with biocompatible and functionalizable surfaces. In addition, fluorescent properties of the CP-loaded PLGA NPs (CPL NPs) could be fine-tuned by loading different types of CPs into the PLGA matrix. Four types of CPL NPs are prepared with a volume-average hydrodynamic diameter ranging from 243 to 272,nm. The application of CPL NPs for bio-imaging is demonstrated through incubation with MCF-7 breast cancer cells. Confocal laser scanning microscopy studies reveal that the CPL NPs are internalized in cytoplasm around the nuclei with intense fluorescence. After conjugation with folic acid, cellular uptake of the surface-functionalized CPL NPs is greatly enhanced via receptor-mediated endocytosis by MCF-7 breast cancer cells, as compared to that for NIH/3T3 fibroblast cells, which indicates a selective targeting effect of the folate-functionalized CPL NPs in cellular imaging. The merits of CPL NPs, such as low cytotoxicity, high fluorescence, good photostability, and feasible surface functionalization, will inspire extensive study of CPL NPs as a new generation of probes for specific biological imaging and detection. [source] A General Strategy to Disperse and Functionalize Carbon Nanotubes Using Conjugated Block CopolymersADVANCED FUNCTIONAL MATERIALS, Issue 3 2009Jianhua Zou Abstract A general strategy to disperse and functionalize pristine carbon nanotubes in a single-step process is developed using conjugated block copolymers. The conjugated block copolymer contains two blocks: a conjugated polymer block of poly(3-hexylthiophene), and a functional non-conjugated block with tunable composition. When the pristine carbon nanotubes are sonicated with the conjugated block copolymers, the poly(3-hexylthiophene) blocks bind to the surface of de-bundled carbon nanotubes through non-covalent ,,, interactions, stabilizing the carbon nanotube dispersion, while the functional blocks locate at the outer surface of carbon nanotubes, rendering the carbon nanotubes with desired functionality. In this paper, conjugated block copolymers of poly(3-hexylthiophene)- b -poly(methyl methacrylate), poly(3-hexylthiophene)- b -poly(acrylic acid), and poly(3-hexylthiophene)- b -poly(poly(ethylene glycol) acrylate) are used to demonstrate this general strategy. [source] Asymmetric Reduction of Activated Alkenes by Pentaerythritol Tetranitrate Reductase: Specificity and Control of Stereochemical Outcome by Reaction OptimisationADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 17 2009Anna Fryszkowska Abstract We show that pentaerythritol tetranitrate reductase (PETNR), a member of the ,ene' reductase old yellow enzyme family, catalyses the asymmetric reduction of a variety of industrially relevant activated ,,,-unsaturated alkenes including enones, enals, maleimides and nitroalkenes. We have rationalised the broad substrate specificity and stereochemical outcome of these reductions by reference to molecular models of enzyme-substrate complexes based on the crystal complex of the PETNR with 2-cyclohexenone 4a. The optical purity of products is variable (49,99% ee), depending on the substrate type and nature of substituents. Generally, high enantioselectivity was observed for reaction products with stereogenic centres at C, (>99% ee). However, for the substrates existing in two isomeric forms (e.g., citral 11a or nitroalkenes 18,19a), an enantiodivergent course of the reduction of E/Z -forms may lead to lower enantiopurities of the products. We also demonstrate that the poor optical purity obtained for products with stereogenic centres at C, is due to non-enzymatic racemisation. In reactions with ketoisophorone 3a we show that product racemisation is prevented through reaction optimisation, specifically by shortening reaction time and through control of solution pH. We suggest this as a general strategy for improved recovery of optically pure products with other biocatalytic conversions where there is potential for product racemisation. [source] Challenges of antiangiogenic cancer therapy: trials and errors, and renewed hopeJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 3 2007Miguel Ángel Medina ,,Introduction ,,What can we learn from the previous failures? ,,Signs of hope ,,Another turn of the screw: a surrogate marker, at last ,,Future avenues for the vascular therapy of cancer Abstract Angiogenesis inhibition has been proposed as a general strategy to fight cancer. However, in spite of the promising preclinical results, a first generation of antiangiogenic compounds yielded poor results in clinical trials. Conceptual errors and mistakes in the design of trials and in the definition of clinical end-points could account for these negative results. In this context of discouraging results, a second generation of antiangiogenic therapies is showing positive results in phases II and III trials at the beginning of the twenty-first century. In fact, several combined treatments with conventional chemotherapy and antiangiogenic compounds have been recently approved. The discovery and pharmacological development of future generations of angiogenesis inhibitors will benefit from further advances in the understanding of the mechanisms involved in human angiogenesis. New styles of trials are necessary, to avoid missing potential therapeutic effects. Different clinical end-points, new surrogate biomarkers and methods of imaging will be helpful in this process. Real efficacy in clinical trials may come with the combined use of antiangiogenic agents with conventional chemotherapy or radiotherapy, and combinations of several antiangiogenic compounds with different mechanisms of action. Finally, the existing antiangiogenic strategies should include other approaches such as vascular targeting or angioprevention. [source] O -acetylation of GD3 prevents its apoptotic effect and promotes survival of lymphoblasts in childhood acute lymphoblastic leukaemiaJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 3 2008Kankana Mukherjee Abstract We have previously demonstrated induction of O -acetylated sialoglycoproteins on lymphoblasts of childhood acute lymphoblastic leukaemia (ALL). These molecules promote survival of lymphoblasts by preventing apoptosis. Although O -acetylated sialoglycoproteins are over expressed, the status of O -acetylation of gangliosides and their role in lymphoblasts survival remains to be explored in ALL patients. Here, we have observed enhanced levels of 9- O -acetylated GD3 (9- O -AcGD3) in the lymphoblasts of patients and leukaemic cell line versus disialoganglioside GD3 in comparison to the normal cells. Localization of GD3 and 9- O -AcGD3 on mitochondria of patient's lymphoblasts has been demonstrated by immuno-electron microscopy. The exogenous administration of GD3-induced apoptosis in lymphoblasts as evident from the nuclear fragmentation and sub G0/G1 apoptotic peak. In contrast, 9- O -AcGD3 failed to induce such apoptosis. We further explored the mitochondria-dependent pathway triggered during GD3-induced apoptosis in lymphoblasts. GD3 caused a time-dependent depolarization of mitochondrial membrane potential, release of cytochrome c and 7.4- and 8-fold increased in caspase 9 and caspase 3 activity respectively. However, under identical conditions, an equimolar concentration of 9- O -AcGD3 failed to induce similar effects. Interestingly, 9- O -AcGD3 protected the lymphoblasts from GD3-induced apoptosis when administered in equimolar concentrations simultaneously. In situ de- O -acetylation of 9- O -AcGD3 with sodium salicylate restores the GD3-responsiveness to apoptotic signals. Although both GD3 and 9- O -acetyl GD3 localize to mitochondria, these two structurally related molecules may play different roles in ALL-disease biology. Taken together, our results suggest that O -acetylation of GD3, like that of O -acetylated sialoglycoproteins, might be a general strategy adopted by leukaemic blasts towards survival in ALL. J. Cell. Biochem. 105: 724,734, 2008. © 2008 Wiley-Liss, Inc. [source] A novel approach for screening discrete variations in organic synthesisJOURNAL OF CHEMOMETRICS, Issue 5 2001Rolf Carlson Abstract In this paper we present a general strategy for screening discrete variations in organic synthesis. The strategy is based upon principal properties, i.e. principal component characterization of the constituents defining the reaction system. The first step is to select subsets of test items from each class of constituents defining the reaction space, i.e. substrates, reagents, solvents, catalysts, etc., so that the selected items from each class cover the properties considered. The second step is to construct a candidate matrix which contains all possible combinations of the items in the subsets. This matrix is a full multilevel factorial design. The third step is to assign a tentative model for the screening experiment and to construct the corresponding candidate model matrix. The fourth step is to select experiments to yield an experimental design that spans the variable space efficiently and that also gives good estimates of the model parameters. We present an algorithm that uses singular value decomposition to select experiments. The proposed strategy is then illustrated with an example of the Fischer indole synthesis. Copyright © 2001 John Wiley & Sons, Ltd. [source] Aziridines as templates: A general strategy for the stereospecific synthesis of 2-azetidinonesJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 1 2006S. D. Sharma Various routes to a variety of azridine-2-carboxylates have been described and the stereochemistry of these compounds has been determined by spectroscopic methods. Further, greater diversity of ,-lactams via ring expansion of these azridines-2-carboxylates were obtained by a general, efficient and direct stereospecific approach. [source] Integrated estimation of measurement error with empirical process modeling,A hierarchical Bayes approachAICHE JOURNAL, Issue 11 2009Hongshu Chen Abstract Advanced empirical process modeling methods such as those used for process monitoring and data reconciliation rely on information about the nature of noise in the measured variables. Because this likelihood information is often unavailable for many practical problems, approaches based on repeated measurements or process constraints have been developed for their estimation. Such approaches are limited by data availability and often lack theoretical rigor. In this article, a novel Bayesian approach is proposed to tackle this problem. Uncertainty about the error variances is incorporated in the Bayesian framework by setting noninformative priors for the noise variances. This general strategy is used to modify the Sampling-based Bayesian Latent Variable Regression (Chen et al., J Chemom., 2007) approach, to make it more robust to inaccurate information about the likelihood functions. Different noninformative priors for the noise variables are discussed and unified in this work. The benefits of this new approach are illustrated via several case studies. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Making Sense of Inquiry SensemakingJOURNAL OF MANAGEMENT STUDIES, Issue 1 2000Andrew D. Brown This paper presents a discourse analysis of a report of a tribunal of inquiry in order to further our understanding of inquiry team sensemaking. The subject of the paper is the report of the Allitt Inquiry into attacks on children on Ward 4 at Grantham and Kesteven Hospital in the UK. Premised on an understanding of the report as an exercise in sensemaking, and sensemaking as a narrative process, the paper illustrates how authorial strategies centred on issues of normalization, observation and absolution are employed to create a rhetorical and verisimilitudinous artefact. This, it is argued, is accomplished as part of a more general strategy of depoliticizing the disaster event, legitimating social institutions (especially those connected with the medical profession), ameliorating anxieties by elaborating fantasies of omnipotence and control, and thenceforth acting as a sensitizing narrative archetype. [source] A general strategy for highly efficient nanoparticle dispersing agents based on hybrid dendritic linear block copolymersJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 5 2009Robert Vestberg Abstract A modular approach to the synthesis of a library of hybrid dendritic-linear copolymers was developed based on RAFT polymerization from monodisperse dendritic macroRAFT agents. By accurately controlling the molecular weight of the linear block, generation number of the dendrimer and the nature of the dendritic chains ends, the performance of these hybrid block copolymers as dispersing agents was optimized for a range of nanoparticles. For titanium dioxide nanoparticles, dispersion in a poly(methyl methacrylate) matrix was maximized with a second generation dendrimer containing four carboxylic acid end groups, and the quality of dispersion was observed to be superior to commercial dispersing agents for TiO2. This approach also allowed novel hybrid dendritic-linear dispersing agents to be prepared for the dispersion of Au and CdSe nanoparticles based on disulphide and phosphine oxide end groups, respectively. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1237,1258, 2009 [source] Prospective real-time correction for arbitrary head motion using active markersMAGNETIC RESONANCE IN MEDICINE, Issue 4 2009Melvyn B. Ooi Abstract Patient motion during an MRI exam can result in major degradation of image quality, and is of increasing concern due to the aging population and its associated diseases. This work presents a general strategy for real-time, intraimage compensation of rigid-body motion that is compatible with multiple imaging sequences. Image quality improvements are established for structural brain MRI acquired during volunteer motion. A headband integrated with three active markers is secured to the forehead. Prospective correction is achieved by interleaving a rapid track-and-update module into the imaging sequence. For every repetition of this module, a short tracking pulse-sequence remeasures the marker positions; during head motion, the rigid-body transformation that realigns the markers to their initial positions is fed back to adaptively update the image-plane,maintaining it at a fixed orientation relative to the head,before the next imaging segment of k -space is acquired. In cases of extreme motion, corrupted lines of k -space are rejected and reacquired with the updated geometry. High-precision tracking measurements (0.01 mm) and corrections are accomplished in a temporal resolution (37 ms) suitable for real-time application. The correction package requires minimal additional hardware and is fully integrated into the standard user interface, promoting transferability to clinical practice. Magn Reson Med, 2009. © 2009 Wiley-Liss, Inc. [source] ARE MENTAL STATE WELFARISM AND OUR CONCERN FOR NON-EXPERIENTIAL GOALS INCOMPATIBLE?PACIFIC PHILOSOPHICAL QUARTERLY, Issue 1 2007EDUARDO RIVERA-LÓPEZ If there is not, then we should reject mental state welfarism. My thesis is that there is such a version. My argument relies on the distinction between "reality-centered desires" and "experience-centered desires". Mental state welfarism can accommodate our reality-centered desires and our desire that they be objectively satisfied. My general strategy is, at the level of the value theory, somewhat analogous to the strategy that indirect consequentialism applies at the level of moral obligation theory. To test my argument, I appeal to Nozick's well-known example of the Experience Machine. [source] Insecticide resistance management strategies against the western flower thrips, Frankliniella occidentalisPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 11 2008Pablo Bielza Abstract Western flower thrips (WFT), Frankliniella occidentalis (Pergande), is an economically important pest of a wide range of crops grown throughout the world. Insecticide resistance has been documented in many populations of WFT. Biological and behavioural characteristics and pest management practices that promote insecticide resistance are discussed. In addition, an overview is provided of the development of insecticide resistance in F. occidentalis populations and the resistance mechanisms involved. Owing to widespread resistance to most conventional insecticides, a new approach to insecticide resistance management (IRM) of F. occidentalis is needed. The IRM strategy proposed consists of two parts. Firstly, a general strategy to minimise the use of insecticides in order to reduce selection pressure. Secondly, a strategy designed to avoid selection of resistance mechanisms, considering cross-resistance patterns and resistance mechanisms. Copyright © 2008 Society of Chemical Industry [source] Quantitative specificity-based display library screening identifies determinants of antibody-epitope binding specificity,PROTEIN SCIENCE, Issue 9 2009Sejal S. Hall Abstract Despite the critical importance of molecular specificity in bimolecular systems, in vitro display technologies have been applied extensively for affinity maturation of peptides and antibodies without explicitly measuring the specificity of the desired interaction. We devised a general strategy to measure, screen, and evolve specificity of protein ligand interactions analogous to widely used affinity maturation strategies. The specificity of binding to target and nontarget antibodies labeled with spectrally distinct fluorophores was measured simultaneously in protein mixtures via multiparameter flow cytometry, thereby enabling screening for high target antibody specificity. Isolated antibody specific ligands exhibited varying specificity, revealing critical amino acid determinants for target recognition and nontarget avoidance in complex mixtures. Molecular specificity in the mixture was further enhanced by quantitative directed evolution, yielding a family of epitopes exhibiting improved specificities equivalent, or superior to, the native peptide antigen to which the antibody was raised. Specificity screening simultaneously favored affinity, yielding ligands with three-fold improved affinity relative to the parent epitope. Quantitative specificity screening will be useful to screen, evolve, and characterize the specificity of protein and peptide interactions for molecular recognition applications. [source] Glycoproteomics of N -glycosylation by in-gel deglycosylation and matrix-assisted laser desorption/ionisation-time of flight mass spectrometry mapping: Application to congenital disorders of glycosylationPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 10 2005Dijana Abstract A general strategy for the structural evaluation of N -glycosylation, a common post-translational protein modification, is presented. The methods for the release of N -linked glycans from the gel-separated proteins, their isolation, purification and matrix-assisted laser desorption/ionisation-mass spectrometry (MALDI-MS) analysis of their mixtures were optimised. Since many glycoproteins are available only at low quantities from sodium dodecyl sulphate-polyacrylamide gel electrophoresis or two-dimensional gels, high attention was paid to obtain N -glycan mixtures representing their actual composition in human plasma by in-gel deglycosylation. The relative sensitivity of solid MALDI matrices for MS analysis of acidic N -glycans was compared. The most favourable results for native acidic N -glycans were obtained with 2,4,6-trihydroxyacetophenone monohydrate/diammoniumcitrate as a matrix. This matrix provided good results for both neutral and acidic mixtures as well as for methylated N -glycans. In the second part of this paper the potential of such an optimised MS strategy alone or in combination with high pH anion-exchange chromatography profiling for the clinical diagnosis of congenital disorders of glycosylation is presented. [source] Space and sustainability: an exploratory essay on the production of social spaces through city-workTHE GEOGRAPHICAL JOURNAL, Issue 3 2007PETER J TAYLOR The purpose of this essay is to locate the making of social spaces as a particularly salient approach for understanding sustainability. Castells' spaces of places and spaces of flows are interpreted generically and a new social theory, Jacobs' moral syndromes, is introduced to underpin the production of these two spatial forms: commercial agents through their network practices make spaces of flows; guardian agents through their territorial practices make spaces of places. Both spaces are considered to be the outcome of city-work. A new division of labour is devised: four primary types of city-work are identified: hinter-work, net-work, territorial-work and hierarch-work. These ideas are considered as tools for thinking about developing spatial policies for sustainability. In conclusion, Jacobs' theory is used to discuss what the general strategy has to be for tackling sustainability. [source] Comparison of PERV genomic locations between Asian and European pigsANIMAL GENETICS, Issue 1 2010W. Y. Jung Summary Xenotransplantation from pigs provides a possible solution to the shortage of human organs for allotransplantation. Porcine endogenous retroviruses (PERVs) are a possible obstacle to using porcine organs in addition to the immunological barriers. Three main types of PERVs (A, B and C) have been previously investigated in diverse pig breeds. To examine the copy numbers of PERVs and their genomic locations in the Korean native pig genome, we screened a BAC (Bacterial Artificial Chromosome) library with PERV-specific protease primers for initial recognition of PERV-positive clones and three sets of envelope-specific primers for the identification of PERV types. A total of 45 PERV-positive clones, nine PERV-A and 36 PERV-B, have been identified from the library screening and the BAC contigs were constructed using the primers designed from BAC end sequences (BESs). These primers were also used for SCH (Somatic Cell Hybrid) and RH (Radiation Hybrid) mapping of the PERV-positive clones. The results indicate that 45 PERV-positive BAC clones belong to nine contigs and a singleton. SCH and IMpRH (INRA-Minnesota Porcine Radiation Hybrid) mapping results indicated that there are at least eight separate PERV genomic locations, consisting of three PERV-A and five PERV-B. One contig could not be mapped, and two contigs are closely located on SSC7. Southern blotting indicates there may be up to 15 additional sites. Further investigation of these clones will contribute to a general strategy to generate PERV-free lines of pigs suitable for xenotransplantation. [source] | |||||||||||||||||||||||||||||||||||||