1,547 research outputs found
Chelator free gallium-68 radiolabelling of silica coated iron oxide nanorods via surface interactions
The commercial availability of combined magnetic resonance imaging (MRI)/positron emission tomography (PET) scanners for clinical use has increased demand for easily prepared agents which offer signal or contrast in both modalities. Herein we describe a new class of silica coated iron–oxide nanorods (NRs) coated with polyethylene glycol (PEG) and/or a tetraazamacrocyclic chelator (DO3A). Studies of the coated NRs validate their composition and confirm their properties as in vivo T₂ MRI contrast agents. Radiolabelling studies with the positron emitting radioisotope gallium-68 (t1/2 = 68 min) demonstrate that, in the presence of the silica coating, the macrocyclic chelator was not required for preparation of highly stable radiometal-NR constructs. In vivo PET-CT and MR imaging studies show the expected high liver uptake of gallium-68 radiolabelled nanorods with no significant release of gallium-68 metal ions, validating our innovation to provide a novel simple method for labelling of iron oxide NRs with a radiometal in the absence of a chelating unit that can be used for high sensitivity liver imaging
Professors’ perceptions of distance education in virtual environments: The case of the Education Faculty of University of Al-Yarmouk (Jordan)
The goal of this study is to determine the perceptions that the teaching staff of the Faculty of Education at University of Al-Yarmouk (Jordan) have of the implementation of distance learning in virtual environments, more specifically, the professors’ opinion of the potential and limitations of this educational strategy. To fulfil this goal, we developed a survey study. The main findings indicate that, overall, distance education in virtual environments has earned a good opinion among the professors who participated in the study, although the potential benefits of distance education are the most highly valued dimension. The professors rank the dimensions of goals and difficulties in implementing this educational strategy second, and planning the third and lowest dimension. Further, some identifying variables (e.g., department, gender) show statistically significant differences relative to the dimensions of the scale used
Effect of Drought Stress on Essential Oil Composition of Thymus vulgaris L. (Chemotype 1, 8-cineole) from wild populations of Eastern Iberian Peninsula
[EN] 1,8-cineole defines a typical chemotype of Thymus vulgaris L. in Iberian Peninsula. This compound has a wide range of potentially useful bioactive properties. In order to study the influence of drought stress in the essential oil (EO) composition of this chemotype, sixty plants from six wild populations of Eastern Iberian Peninsula were distilled and analyzed by GC and GC/MS. The harvest dates (May and August) were selected in such a way that the typical summer drought in Mediterranean climates was the critical factor affecting EO composition. Despite the high intrapopulational variability, significant increases of 1,8-cineole were found after the drought period (21.8%-43.2%, in May, up to 42.6%-68.5% in August). On the other hand, individuals from one of the populations showed different profiles rich in linalool and camphor or sesquiterpenoid compounds, such as a-cadinol.Llorens Molina, JA.; Vacas González, S. (2016). Effect of Drought Stress on Essential Oil Composition of Thymus vulgaris L. (Chemotype 1, 8-cineole) from wild populations of Eastern Iberian Peninsula. Journal of Essential Oil Research. 29(2):145-155. doi:10.1080/10412905.2016.1211561S14515529
Los clubes deportivos de natación de Cataluña en el actual contexto competitivo del sector de las instalaciones deportivas
Swimming clubs are non-profit entities for sports and social purposes. The general objective of the study was to know the management of swimming clubs in Catalonia, fulfilling their social and sports role in the current competitive environment of sports facilities. As specific objectives were to know their values on management indicators, as well as to know if significant differences between swimming clubs are found, taking in consideration their areas and sports offer. The study sample consists of 19 swimming clubs of Catalonia. The data collection instrument was a questionnaire adapted to the objectives of the study, administered by email to the managers of each club. The clubs obtain the necessary income to achieve their sporting and social goals thanks to the fees of their members. It was found significant differences between them according to the spaces and sports offer in different management indicators analyzed.Los clubes de natación son entidades sin ánimo de lucro con fines deportivos y sociales. El objetivo general del estudio fue conocer la gestión de los clubes de natación en Cataluña cumpliendo su función social y deportiva en el actual entorno competitivo de instalaciones deportivas. Los objetivos específicos fueron conocer sus valores en indicadores de gestión, así como saber si existen diferencias significativas entre los clubes según sus espacios y oferta deportiva. La muestra del estudio ha sido formada por 19 clubes deportivos de natación de Cataluña. El instrumento de recogida de datos fue un cuestionario adaptado a los objetivos del estudio, administrado por correo electrónico a los gerentes de cada club. Los clubes obtienen los ingresos necesarios para lograr sus fines deportivos y sociales gracias a las cuotas de sus socios. Se encontraron diferencias significativas entre ellos según los espacios y oferta deportiva en diferentes indicadores de gestión analizados
Ultrastructure of the Plasmodial Development of Myxobolus insignis (Myxozoa), Infecting the Amazonian Fish Semaprochilodus insignis (Prochilodontidae)
This study used light and electron microscopy to describe a myxosporean, polysporic, histozoic plasmodium infecting the gill filaments of the freshwater teleost, Semaprochilodus insignis, specimens of which were collected from the Trombetas River (Central Amazonian Region, Brazil). Ultrastructural analyses of the fish-infecting spores identified the parasite as Myxobolus insignis, an organism that occurs within whitish unequal-sized plasmodia located in the intralamellar epithelium of the gill. Based on the observed morphological and ultrastructural features of the plasmodia in this study three stages in the plasmodial evolution were distinguished, related to the sporogonic stages of Myxobolus insignis. The plasmodium walls were also found to constitute a number of layers of fibroblasts, surrounded by collagen fibres, which displayed different morphological arrangements according to the different phases of evolution. This represents the first time such ultrastructural features have been described in detail for Myxobolus insignis plasmodia and offers potentially significant points of comparison with plasmodia from other species of myxosporea
Experimental characterization of an ORC (organic Rankine cycle) for power and CHP (combined heat and power) applications from low grade heat sources
An ORC (organic Rankine cycle) module, designed and built for a specific CHP (combined heat and power)) application, is tested in this paper. The aim of the work is to characterize the system performance in the operating range allowed by the ORC. For this purpose, a test procedure has been conducted in a test bench. The heat source has been simulated through a natural gas boiler and a thermal oil heat transfer loop to control the temperature in the low grade range of 90 °C 150 °C. The heat sink has been developed using a dry cooler to control the hot water temperature in the range of 30 °C, corresponding to a power application, to 80 °C, of a small-scale CHP application that provides hot water at 90 °C. Thereby, the results show that the thermal power captured by the ORC, electricity and useful heat produced, increase with the rise of the thermal oil temperature and larger pressure ratios. Moreover, the expander electrical isentropic effectiveness is maximized about 70% for a pressure ratio suitable for a CHP system. The cycle efficiency slightly continues increasing for higher pressure ratios, up to a net electrical efficiency of about 8%.The authors want to acknowledge all the invaluable cooperation of Rank (R), the ORC manufacturer, for its support in this project. Also to thank greatly the Jaume I University for its financial support under the PhD grant PREDOC/2013/28 of 'Convocatoria d'ajudes predoctorals per a la formacio de personal investigador del Pla de promocio de la investigacio de la Universitat Jaume I de Castello (Spain)'.Peris Pérez, B.; Navarro Esbri, J.; Molés Ribera, F.; González, M.; Mota Babiloni, A. (2015). Experimental characterization of an ORC (organic Rankine cycle) for power and CHP (combined heat and power) applications from low grade heat sources. Energy. 82:269-276. https://doi.org/10.1016/j.energy.2015.01.037S2692768
Team sports performance analysed through the lens of social network theory: implications for research and practice
This paper discusses how social network analyses and graph theory can be implemented in team sports performance analyses to evaluate individual (micro) and collective (macro) performance data, and how to use this information for designing practice tasks. Moreover, we briefly outline possible limitations of social network studies and provide suggestions for future research. Instead of cataloguing discrete events or player actions, it has been argued that researchers need to consider the synergistic interpersonal processes emerging between teammates in competitive performance environments. Theoretical assumptions on team coordination prompted the emergence of innovative, theoretically-driven methods for assessing collective team sport behaviours. Here, we contribute to this theoretical and practical debate by conceptualising sports teams as complex social networks. From this perspective, players are viewed as network nodes, connected through relevant information variables (e.g., a ball passing action), sustaining complex patterns of interaction between teammates (e.g., a ball passing network). Specialized tools and metrics related to graph theory could be applied to evaluate structural and topological properties of interpersonal interactions of teammates, complementing more traditional analysis methods. This innovative methodology moves beyond use of common notation analysis methods, providing a richer understanding of the complexity of interpersonal interactions sustaining collective team sports performance. The proposed approach provides practical applications for coaches, performance analysts, practitioners and researchers by establishing social network analyses as a useful approach for capturing the emergent properties of interactions between players in sports teams
Modelling and simulation of a stationary high-rise elevator system to predict the dynamic interactions between its components
In a high-rise elevator system lateral vibrations of the suspension and compensating ropes, coupled with vertical motions of the car and counterweight are induced by the building structure motions. When the frequency of the building coincides with the fundamental natural frequency of the ropes, large resonance whirling motions of the ropes result. This phenomenon leads to impacts of the ropes on the elevator walls, large displacements of the car and counterweight making the building and elevator system unsafe. This paper presents a comprehensive mathematical model of a high-rise elevator system taking into account the combined lateral stiffness of the roller guides and guide rails. The results and analysis presented in the paper demonstrate frequency curve veering phenomena and a wide range of resonances that occur in the system. A case study is presented when the car is parked at a landing level where the fundamental natural frequencies of the car, suspension and compensating rope system coincide with one of the natural frequencies of the high-rise building. The results show a range of nonlinear dynamic interactions between the components of the elevator system that play a significant role in the operation of the entire installation
Status and Recent Results of the Acoustic Neutrino Detection Test System AMADEUS
The AMADEUS system is an integral part of the ANTARES neutrino telescope in
the Mediterranean Sea. The project aims at the investigation of techniques for
acoustic neutrino detection in the deep sea. Installed at a depth of more than
2000m, the acoustic sensors of AMADEUS are based on piezo-ceramics elements for
the broad-band recording of signals with frequencies ranging up to 125kHz.
AMADEUS was completed in May 2008 and comprises six "acoustic clusters", each
one holding six acoustic sensors that are arranged at distances of roughly 1m
from each other. The clusters are installed with inter-spacings ranging from
15m to 340m. Acoustic data are continuously acquired and processed at a
computer cluster where online filter algorithms are applied to select a
high-purity sample of neutrino-like signals. 1.6 TB of data were recorded in
2008 and 3.2 TB in 2009. In order to assess the background of neutrino-like
signals in the deep sea, the characteristics of ambient noise and transient
signals have been investigated. In this article, the AMADEUS system will be
described and recent results will be presented.Comment: 7 pages, 8 figures. Proceedings of ARENA 2010, the 4th International
Workshop on Acoustic and Radio EeV Neutrino Detection Activitie
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