Defined Set (defined + set)

Distribution by Scientific Domains


Selected Abstracts


Configuration Space Control for Wendelstein 7-X

CONTRIBUTIONS TO PLASMA PHYSICS, Issue 8 2010
T. Dodson
Abstract The Wendelstein 7-X stellarator (W7-X) is a superconducting fusion experiment presently under construction at the Greifswald branch of the Max-Planck-Institut für Plasmaphysik in Greifswald, Germany. W7-X is a device with extreme geometrical complexity due to the close-packing of components inside the cryostat and their complex three-dimensional shapes. The task of the Configuration Space Control department is to ensure that these components do not collide with each other under the defined set of configurations such as during assembly, at cool down, or during operation at various coil currents, among others. To fulfill this task, sophisticated tools and procedures were developed and implemented within the realm of a newly founded division that focuses on design, configuration control, and configuration management. This paper will discuss the Configuration Space Control process, explore the advantages to the project resulting from the process, and demonstrate its application in the analysis of the cryogenic cooling pipes of Module 5 (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Characterizing regime shifts in the marine environment

FISH AND FISHERIES, Issue 2 2006
Kathryn Lees
Abstract Recent years have seen a plethora of studies reporting that ,regime shifts' have occurred in the North Atlantic and Pacific Oceans during the last century. In many cases, the criteria used to distinguish a regime shift have not been explicitly stated. In other cases, a formal definition has been proposed and the data set assessed against it. Developing a universal quantitative definition for identifying and distinguishing between purported climatic and ecological regime shifts has proved problematic as many authors have developed criteria that seem unique to the system under study. Consequently, they throw little light on the drivers of ecological regime shifts. Criteria used to define regime shifts are reviewed and on the basis of evidence from purported regime shifts, common characteristics in the speed and amplitude of the changes and the duration of quasi-stable states are used to propose a more clearly defined set of criteria for defining climatic and ecological regime shifts. Causal drivers of regime shifts are explored using correlation analysis. Limitations of these methods are discussed. [source]


Design of Experiments (DOE) for the Optimization of Titania,hydroxyapatite Functionally Graded Coatings

INTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 4 2009
Valeria Cannillo
Titania,hydroxyapatite functionally graded coatings were deposited on titanium alloy substrates by plasma spraying. Because it was necessary to spray together the titania and the hydroxyapatite powders to obtain the graded system, the first target of the present study was to optimize the process parameters in order to obtain a high-quality coating. A 23 Design of Experiments was applied to define the optimal values of plasma torch power, hydrogen flux, and spraying distance. This defined set of parameters (38 kW, 5 SLPM, and 90 mm, respectively) was used to spray the most promising graded coating, which was characterized and postheat treated. [source]


Sustained delivery and efficacy of polymeric nanoparticles containing osteopontin and bone sialoprotein antisenses in rats with breast cancer bone metastasis

INTERNATIONAL JOURNAL OF CANCER, Issue 7 2010
Victoria Elazar
Abstract Poor prognosis in mammary carcinoma is associated with a certain expression profile of a defined set of genes including osteopontin and bone sialoprotein. Efficient and specific delivery of antisenses (AS) and a protection of the sequences from degradation are the crucial conditions for AS therapeutic efficiency. We hypothesized that effective and safe AS delivery direceted against these genes could be achieved by polymeric nanoparticles (NP) fabricated from a biocompatible polymer. Due to their nano-size range and small negative charge, AS-NP can overcome the absorption barrier offering increased resistance to nuclease degradation, sustained duration of AS administration, and consequently, prolonged antisense action. The ASs designed against OPN and BSP-II were successfully encapsulated in NP composed of the biodegradable and biocompatible polylactide- co -glycolide polymer (PLGA), exhibiting sustained release and stability of the ASs. The therapeutic efficacy of the AS-NP delivery system was examined in vitro, and in a breast cancer bone metastasis animal model of MDA-MB-231 human breast cancer cells in nude rats. Treatment with OPN-AS or BSP-AS loaded NP in comparison with osmotic mini-pumps (locoregional injection and SC implants, respectively) resulted in a significant decrease in both, tumor bone metastasis incidence and in the size of the lesions in rats with metastases. Despite its smaller dose, AS-NP exhibited a better therapeutic efficacy than osmotic mini-pumps in terms of lesion ratio at later time periods (8,12 weeks). It may be concluded that AS delivery by NP is a promising therapeutic modality providing stability of the encapsulated AS and a sustained release. [source]


Functional evolution of Hox proteins in arthropods

BIOESSAYS, Issue 9 2002
Michel Vervoort
It is presumed that the evolution of morphological diversity in animals and plants is driven by changes in the developmental processes that govern morphology, hence basically by changes in the function and/or expression of a defined set of genes that control these processes. A large body of evidence has suggested that changes in developmental gene regulation are the predominant mechanisms that sustain morphological evolution, being much more important than the evolution of the primary sequences and functions of proteins. Recent reports1, 2 challenge this idea by highlighting functional evolution of Hox proteins during the evolutionary history of arthropods. BioEssays 24:775,779, 2002. © 2002 Wiley Periodicals, Inc. [source]


Cell-free production of transducible transcription factors for nuclear reprogramming,

BIOTECHNOLOGY & BIOENGINEERING, Issue 6 2009
William C. Yang
Abstract Ectopic expression of a defined set of transcription factors chosen from Oct3/4, Sox2, c-Myc, Klf4, Nanog, and Lin28 can directly reprogram somatic cells to pluripotency. These reprogrammed cells are referred to as induced pluripotent stem cells (iPSCs). To date, iPSCs have been successfully generated using lentiviruses, retroviruses, adenoviruses, plasmids, transposons, and recombinant proteins. Nucleic acid-based approaches raise concerns about genomic instability. In contrast, a protein-based approach for iPSC generation can avoid DNA integration concerns as well as provide greater control over the concentration, timing, and sequence of transcription factor stimulation. Researchers recently demonstrated that polyarginine peptide conjugation can deliver recombinant protein reprogramming factor (RF) cargoes into cells and reprogram somatic cells into iPSCs. However, the protein-based approach requires a significant amount of protein for the reprogramming process. Producing fusion RFs in the large amounts required for this approach using traditional heterologous in vivo production methods is difficult and cumbersome since toxicity, product aggregation, and proteolysis by endogenous proteases limit yields. In this work, we show that cell-free protein synthesis (CFPS) is a viable option for producing soluble and functional transducible transcription factors for nuclear reprogramming. We used an E. coli -based CFPS system to express the above set of six human RFs as fusion proteins, each with a nona-arginine (R9) protein transduction domain. Using the flexibility offered by the CFPS platform, we successfully addressed proteolysis and protein solubility problems to produce full-length and soluble R9-RF fusions. We subsequently showed that R9-Oct3/4, R9-Sox2, and R9-Nanog exhibit cognate DNA-binding activities, R9-Nanog translocates across the plasma and nuclear membranes, and R9-Sox2 exerts transcriptional activity on a known downstream gene target. Biotechnol. Bioeng. 2009; 104: 1047,1058. © 2009 Wiley Periodicals, Inc. [source]


General practitioners' ranking of evidence-based prescribing quality indicators: a comparative study with a prescription database

BRITISH JOURNAL OF CLINICAL PHARMACOLOGY, Issue 2 2006
Ifeanyi Okechukwu
Background To ensure that indicators for assessing prescribing quality are appropriate and relevant, physicians should be involved in their development. How general practitioners (GPs) rank these indicators is not fully understood. Aims (i) To determine how GPs in Ireland rank a set of evidence-based prescribing quality indicators in order of importance and relevance to their practice, and (ii) to compare the GPs' ranking of the defined set of indicators with actual prescribing practice using a prescription database. Methods A postal questionnaire was sent to 105 GPs, who were asked to rank a set of 11 prescribing quality indicators, identified from the literature from most to least important. The results were aggregated and a weighted score for each indicator determined. These same prescribing indicators were then applied to a prescription database to compare the ranking provided with actual prescribing practice. Results Eighty-six GPs (82%) returned the completed questionnaire. The higher ranks were for quality issues,use of inhaled corticosteroids, statins and benzodiazepines. Actual prescribing data showed prolonged use of benzodiazepines in over half of the prescriptions dispensed (n = 18 171), 52.48% (95% confidence interval 51.95, 53.01) and low usage of generic drugs, 17.78% (17.70, 17.90) despite their high ranking by the GPs. Conclusion While GPs have diverse views about the value of different prescribing quality indicators, the results suggest that they do rank evidence-based guidelines on patient management highly, but those based on costs and less evidence the lowest. There was considerable divergence between theory and practice in the application of quality indices. [source]


Cellular configuration of single octopamine neurons in Drosophila

THE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 12 2010
Sebastian Busch
Abstract Individual median octopamine neurons in the insect central nervous system serve as an excellent model system for comparative neuroanatomy of single identified cells. The median octopamine cluster of the subesophageal ganglion consists of defined sets of paired and unpaired interneurons, which supply the brain and subesophageal ganglion with extensive ramifications. The developmental program underlying the complex cellular network is unknown. Here we map the segmental location and developmental origins of individual octopamine neurons in the Drosophila subesophageal ganglion. We demonstrate that two sets of unpaired median neurons, located in the mandibular and maxillary segments, exhibit the same projection patterns in the brain. Furthermore, we show that the paired and unpaired neurons belong to distinct lineages. Interspecies comparison of median neurons revealed that many individual octopamine neurons in different species project to equivalent target regions. Such identified neurons with similar morphology can derive from distinct lineages in different species (i.e., paired and unpaired neurons). J. Comp. Neurol. 518:2355,2364, 2010. © 2010 Wiley-Liss, Inc. [source]