Systematic synthesis and characterization of single-crystal lanthanide phenylphosphonate nanorods

Using low-temperature hydrothermal methods, nanoscale lanthanide phenylphosphonates species with different morphologies, namely, nanoparticles and nanorods, have been systematically synthesized. The possible growth mechanism of these nanorods was discussed. X-ray diffraction, transmission electron microscopy, electron diffraction, and photoluminescence spectra were used to characterize these materials. The photoluminescent properties of EU(O3PC6H5)(HO3PC6H5) and La0.91EU0.09(O3PC6H5)(HO3PC6H5) nanorods were discussed.

Synthesis of Tributylphosphate Capped Luminescent Rare Earth Phosphate Nanocrystals in an Ionic Liquid Microemulsion

Uniform rare earth phosphate (REPO4, RE = La-Tb) nanocrystals were successfully synthesized in a properly designed TBP/[Omim]Cl/H2O (tributylphosphate/1-octyl-3-methyl-imidazolium chloride/water) microemulsion system. The phosphoryl groups anchored the TBP molecules oil the surfaces of the nanocrystals, and this made the nanocrystals easily dispersed in some imidazolium-based ILs. LaPO4:Eu3+ and CePO4:Tb3+ nanocrystals capped with TBP showed bright red and green emission under UV excitation, with enhanced emission intensity and lifetimes compared with the uncapped ones.

CuIn(WO4)(2) nanospindles and nanorods: controlled synthesis and host for lanthanide near-infrared luminescence properties

CuIn(WO4)(2) porous nanospindles and nanorods were synthesized through a low-cost hydrothermal method without introducing any template or surfactants. An interesting formation mechanism, namely "oriented attachment", was observed for the growth of nanorods based on the experimental process and the anisotropic intrinsic crystalline structure of CuIn(WO4)(2), which is uncommon in such a system. The near-infrared luminescence of lanthanide ions (Er, Nd, Yb and Ho) doped CuIn(WO4)(2) nanostructures, especially in the 1300-1600 nm region, was discussed and of particular interest for telecommunications applications. X-Ray diffraction, scanning electron microscopy, transmission electron microscopy, electron diffraction and photoluminescence spectra were used to characterize these materials.

Controlled Synthesis of Ln(3+) (Ln = Tb, Eu, Dy) and V5+ Ion-Doped YPO4 Nano-/Microstructures with Tunable Luminescent Colors

YPO4 nano/microcrystals with multiform crystal phases and morphologies, such as hexagonal nano/submicroprisms, spherical-like nanoparticles, and nanorods with different length/diameter ratios as well as tetragonal nanospindles, have been synthesized via a facile hydrothermal route. A series of controlled experiments indicate that the pH values in the initial solution, phosphorus sources, and the organic additive trisodium citrate (Cit(3-)) are responsible for crystal phase and shape determination of final products. It is found that Cit(3-) as a ligand and shape modifier has the dynamic effect by adjusting the growth rate of different facets under different experimental conditions, resulting in the formation of various geometries of the final products. The possible formation mechanisms for products with diverse architectures have been presented.

A constraint and position identification (CPI) approach for the synthesis of decoupled spatial translational compliant parallel manipulators

This paper introduces a screw theory based method termed constraint and position identification (CPI) approach to synthesize decoupled spatial translational compliant parallel manipulators (XYZ CPMs) with consideration of actuation isolation. The proposed approach is based on a systematic arrangement of rigid stages and compliant modules in a three-legged XYZ CPM system using the constraint spaces and the position spaces of the compliant modules. The constraint spaces and the position spaces are firstly derived based on the screw theory instead of using the rigid-body mechanism design experience. Additionally, the constraint spaces are classified into different constraint combinations, with typical position spaces depicted via geometric entities. Furthermore, the systematic synthesis process based on the constraint combinations and the geometric entities is demonstrated via several examples. Finally, several novel decoupled XYZ CPMs with monolithic configurations are created and verified by finite elements analysis. The present CPI approach enables experts and beginners to synthesize a variety of decoupled XYZ CPMs with consideration of actuation isolation by selecting an appropriate constraint and an optimal position for each of the compliant modules according to a specific application.

The meaning, antecedents and outcomes of employee engagement:a narrative synthesis

The claim that high levels of engagement can enhance organizational performance and individual well-being has not previously been tested through a systematic review of the evidence. To bring coherence to the diffuse body of literature on engagement, the authors conducted a systematic synthesis of narrative evidence involving 214 studies focused on the meaning, antecedents and outcomes of engagement. The authors identified six distinct conceptualizations of engagement, with the field dominated by the Utrecht Group's ‘work engagement’ construct and measure, and by the theorization of engagement within the ‘job demands–resources’ framework. Five groups of factors served as antecedents to engagement: psychological states; job design; leadership; organizational and team factors; and organizational interventions. Engagement was found to be positively associated with individual morale, task performance, extra-role performance and organizational performance, and the evidence was most robust in relation to task performance. However, there was an over-reliance on quantitative, cross-sectional and self-report studies within the field, which limited claims of causality. To address controversies over the commonly used measures and concepts in the field and gaps in the evidence-base, the authors set out an agenda for future research that integrates emerging critical sociological perspectives on engagement with the psychological perspectives that currently dominate the field.

Nanocomposites de Poliuretanos Elastoméricos y Nanotubos de Carbono Multipared

218p. -- Tesis con mención "Doctor europeus" realizada en el periodo de Octubre 2005-Mayo 2010, en el Grupo "Materiales+Tecnologías" (GMT).

Self-Assembled Growth of Agln(MoO4)(2) Submicroplates into Hierarchical Structures and Their Near-Infrared Luminescent Properties

Layer-controlled hierarchical flowerlike AgIn(MoO4)(2) microstructures with "clean" surfaces using submicroplates as building blocks without introducing any template have been fabricated through a low-cost hydrothermal method. The near-infrared luminescence of lanthanide ion (Nd, Er, and Yb) doped AgIn(MoO4)(2) microstructures, in the 1300-1600 nm region, was discussed and is of particular interest for telecommunication applications. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, electron diffraction, and photoluminescence spectra were used to characterize these materials.

Directional modulation transmitter radiation pattern considerations

A pattern synthesis approach is applied to a directional modulation (DM) system. A systematic synthesis procedure is suggested which ensures optimal constellation patterns production along pre-specified communication directions, whereas simultaneously conserving energy dispersal in other directions. In this study, the properties of DM systems synthesised from Gaussian magnitude far-field radiation pattern templates are used to illustrate performance benefits with regards to DM bit error rate response compared with those achieved by a conventional steered array.

Potential uses of Bayesian networks as tools for synthesis of systematic reviews of complex interventions

Bayesian networks (BNs) are tools for representing expert knowledge or evidence. They are especially useful for synthesising evidence or belief concerning a complex intervention, assessing the sensitivity of outcomes to different situations or contextual frameworks and framing decision problems that involve alternative types of intervention. Bayesian networks are useful extensions to logic maps when initiating a review or to facilitate synthesis and bridge the gap between evidence acquisition and decision-making. Formal elicitation techniques allow development of BNs on the basis of expert opinion. Such applications are useful alternatives to ‘empty’ reviews, which identify knowledge gaps but fail to support decision-making. Where review evidence exists, it can inform the development of a BN. We illustrate the construction of a BN using a motivating example that demonstrates how BNs can ensure coherence, transparently structure the problem addressed by a complex intervention and assess sensitivity to context, all of which are critical components of robust reviews of complex interventions. We suggest that BNs should be utilised to routinely synthesise reviews of complex interventions or empty reviews where decisions must be made despite poor evidence.

A Systematic Approach to Synthesis of Verification Test-suites for Modular SoC Designs

Verification is one of the important stages in designing an SoC (system on chips) that consumes upto 70% of the design time. In this work, we present a methodology to automatically generate verification test-cases to verify a class of SoCs and also enable re-use of verification resources created from one SoC to another. A prototype implementation for generating the test-cases is also presented.

A systematic review of controlled trials of interventions to prevent childhood obesity and overweight: realistic synthesis of the evidence

Background: Preventing childhood overweight and obesity has become a major public health issue in developed and developing countries. Systematic reviews of this topic have not provided practice-relevant guidance because of the generally low quality of research and the heterogeneity of reported effectiveness. Aim: To present practice-relevant guidance on interventions to reduce at least one measure of adiposity in child populations that do or do not contain overweight or obese children. Design: Systematic review of eligible randomized, controlled trials or controlled trials using a novel approach to synthesizing the trial results through application of descriptive epidemiological and realistic evaluation concepts. Eligible trials involved at least 30 participants, lasted at least 12 weeks and involved non-clinical child populations. Results: Twenty-eight eligible trials were identified to 30 April 2006. Eleven trials were effective and 17 were ineffective in reducing adiposity. Blind to outcome, the main factor distinguishing effective from ineffective trials was the provision of moderate to vigorous aerobic physical activity in the former on a relatively 'compulsory' rather than 'voluntary' basis. Conclusions: By using a novel approach to synthesizing trials, a decisive role for the 'compulsory' provision of aerobic physical activity has been demonstrated. Further research is required to identify how such activity can be sustained and transformed into a personally chosen behaviour by children and over the life course. (C) 2007 The Royal Institute of Public Health. Published by Elsevier Ltd. All rights reserved.

Targeting the mitochondrial electron transport chain in autism, a systematic review and synthesis of a novel therapeutic approach

Autism is a complex developmental disorder with an unknown etiology and without any curative treatment. The mitochondrial electron transfer chains play a major role in the production of ATP, and the generation and management of reactive oxidative stress (ROS). This paper is a systematic review of the role of the mitochondrial electron transport chain in autism, and a consequent hypothesis for treating autism is synthesized.

An electronic search with pre-specified inclusion criteria was conducted in order to retrieve all the published articles about the mitochondrial electron transport chain in autism. The two databases of PUBMED and Google Scholar were searched.

Iniatives to reduce the use of seclusion and restraints on people with developmental disabilities: a systematic review and quantitative synthesis

Contrary to the expectations articulated in public policy, restrictive interventions are commonly used in support services for people with developmental disabilities. This systematic review and quantitative synthesis was undertaken to investigate whether the use of seclusion and restraints on people with developmental disabilities can be reduced. Searches of the Academic Search Complete, CINAHL, MEDLINE, and PsycINFO electronic databases returned 7226 records, of which 11 met the inclusion criteria for this review. A further 3 papers were obtained through scanning the reference lists of those articles included from the initial literature search. All 14 studies were single-subject designs focusing on initiatives to reduce physical or mechanical restraint. Between the baseline and intervention phases, there were mean reductions in the frequency and duration of restraint use of 79% (SD = 21%, n = 13 subjects from 7 studies) and 45% (SD = 58%, n = 10 subjects from 6 studies), respectively. For studies in which restraint use to manage agitation and aggression was targeted, there was a 79% (SD = 21%, n = 13 subjects from 7 studies) decrease in the frequency and a 28% (SD = 67%, n = 6 subjects from 3 studies) reduction in the duration of restraint. With respect to studies in which restraint use to prevent self-harm was targeted, there was a 71% (SD = 34%, n = 4 subjects from 3 studies) reduction in restraint use. Effect sizes were calculable, using non-overlap approaches, for 9 of the 14 studies. The magnitudes of the effect sizes suggest that, on average, the interventions were effective in reducing the use of restraints. The effects generated in studies where restraint use for self-harm was targeted were typically more pronounced than those in which restraint use for agitation and aggression was addressed. There were broad variations, however, in the percentage reductions in restraint use and in the magnitudes of the effect sizes. Although the findings of this review are encouraging, more research is needed, in which greater attention must be paid to rigorous research design, application, and analysis.

Qualitative synthesis and systematic review in health professions education

Context  Formal qualitative synthesis is the process of pooling qualitative and mixed-method research data, and then drawing conclusions regarding the collective meaning of the research. Qualitative synthesis is regularly used within systematic reviews in the health professions literature, although such use has been heavily debated in the general literature. This controversy arises in part from the inherent tensions found when generalisations are derived from in-depth studies that are heavily context-dependent.Methods  We explore three representative qualitative synthesis methodologies: thematic analysis; meta-ethnography, and realist synthesis. These can be understood across two dimensions: integrative to interpretative, and idealist to realist. Three examples are used to illustrate the relative strengths and limitations of these approaches.Discussion  Against a backdrop of controversy and diverse methodologies, readers must take a critical stand when reading literature reviews that use qualitative synthesis to derive their findings. We argue that notions of qualitative rigour such as transparency and acknowledgment of the researchers’ stance should be applied to qualitative synthesis.