排序方式： 共有55条查询结果，搜索用时 219 毫秒
31.
Ioannis Rabias Danai Tsitrouli Eleni Karakosta Thomas Kehagias Georgios Diamantopoulos Michael Fardis Dimosthenis Stamopoulos Thomas G. Maris Polykarpos Falaras Nikolaos Zouridakis Nikolaos Diamantis Georgios Panayotou Dimitrios A. Verganelakis Garyfalia I. Drossopoulou Effie C. Tsilibari Georgios Papavassiliou 《Biomicrofluidics》2010,4(2)
One of the most significant challenges implementing colloidal magnetic nanoparticles in medicine is the efficient heating of microliter quantities by applying a low frequency alternating magnetic field. The ultimate goal is to accomplish nonsurgically the treatment of millimeter size tumors. Here, we demonstrate the synthesis, characterization, and the in vitro as well as in vivo efficiency of a dextran coated maghemite (γ-Fe2O3) ferrofluid with an exceptional response to magnetic heating. The difference to previous synthetic attempts is the high charge of the dextran coating, which according to our study maintains the colloidal stability and good dispersion of the ferrofluid during the magnetic heating stage. Specifically, in vitro 2 μl of the ferrofluid gives an outstanding temperature rise of 33 °C within 10 min, while in vivo treatment, by infusing 150 μl of the ferrofluid in animal model (rat) glioma tumors, causes an impressive cancer tissue dissolution. 相似文献
32.
Morphology of the deltoid muscles in elite tennis players 总被引：1，自引：0，他引：1
Mavidis A Vamvakoudis E Metaxas T Stefanidis P Koutlianos N Christoulas K Karamanlis A Mandroukas K 《Journal of sports sciences》2007,25(13):1501-1506
The aim of this study was to examine the deltoid muscle properties of the dominant and non-dominant arm of Greek professional male tennis players. Eight male tennis players (mean age 22.0 years, s = 3.2) were subjected to biopsy of the deltoid muscle of both arms. Adenosine triphosphate (ATPase) histochemistry and myosin heavy chain (MHC) composition were performed on the samples with homogenate electrophoresis. No significant differences were observed in the percentage of types I, IIa, IIab, and IIb muscle fibres between the deltoid muscles of the two arms. Types I, IIa, and IIx muscle fibres of the dominant and non-dominant deltoid muscles did not differ significantly for MHC isoform composition. Type IIab muscle fibres showed a similar cross-sectional area (CSA) percentage distribution between the two arms. The CSA percentage for types I, IIa, and IIb muscle fibers did not differ significantly between the dominant and the non-dominant arm. We conclude therefore that regular tennis training probably does not lead to any significant changes in the muscle fibre types of the dominant and non-dominant arms of elite tennis players. 相似文献
33.
Nikolaos Amanatidis 《Education and Information Technologies》2014,19(2):307-326
To meet the increasing demand for change in the incorporation of ICT in education the Greek Ministry of Education and the Institute of Educational Policy of Greece, launched a nationwide project of in-service training (INSET) of teachers of the second level, training of teachers in the use and evaluation of ICT pedagogy in classroom instruction. The main focus of the study was to evaluate the implementation and effectiveness of this in-service training in the pedagogic use of ICT in classroom-based instruction. Through the data collected and analyzed it is argued that a successful training course could be associated with the selection and utilization of specific research and instruction theories. These theories tailored to the acknowledged different profiles of the teacher-trainees as well as the time and setting of the course could promote effectiveness and produce fruitful outcomes. 相似文献
34.
Anastasios J. Sakalis Nikolaos A. Kazakis Nikolaos Merousis Nestor C. Tsirliganis 《Journal of Cultural Heritage》2013,14(6):485-498
Various types of Late Neolithic decorated pottery excavated in Polyplatanos (Imathia, Greece) such as Crusted (C), Classical Dimini (CD), Black-on-Red (BoR), Cream-on-Red (CoR) and Graphite (G) were archaeometrically studied in order to investigate their provenance and to clarify specific technological features. The clay bodies, the paints and the slips were stereoscopically analyzed, while their elemental composition was determined, using non-destructive multi-elemental micro X-ray fluorescence spectroscopy. Furthermore, the analytical data were statistically treated using multivariate exploratory techniques (Principal Component Analysis, PCA). As a result, novel technological information was derived especially concerning the Crusted type ceramics, which have not been widely examined by archaeometric means up to now, while useful provenance associations were also derived from the statistical combination of the studied groups. 相似文献
35.
Argyris G. Toubekis Nikolaos Beidaris Petros G. Botonis Maria Koskolou 《Journal of sports sciences》2017,35(11):1025-1033
The purpose of this study was to examine the metabolic responses during submaximal swimming with self-selected normal breathing (N) and prolonged expiration along with reduced frequency breathing (RB). Ten male swimmers (age: 23.1 ± 2.2 years; VO2max: 47.3 ± 7.2 ml · kg?1 · min?1) performed 75-, 100-, 175-, 200-, 275-, 300-, 375- and 400-m trials with N and RB at intensity corresponding to 90% of the critical speed. In RB condition, all trials longer than 75 m were interspersed with 25 m of self-selected N in regular intervals. In RB, oxygen saturation during recovery was decreased compared to starting values after 75, 100, 175, 275 and 375 m (78–91%, P < 0.05), while it remained unchanged after all trials in N condition (98 ± 2%, P > 0.05). Lactate concentration was higher in RB than in N after 400 m (4.3 ± 1.5 vs. 3.3 ± 1.7 mmol · l?1, P < 0.05). During recovery after the 375-m trial, partial pressure of carbon dioxide was increased and pH was decreased in RB compared to N condition. Prolonged expiration along with RB provokes severe hypoxemia during the recovery period after swimming, which is restored with self-selected N during submaximal swimming. 相似文献
36.
37.
Nikolaos Tselios Nikolaos Avouris Vassilis Komis 《Education and Information Technologies》2008,13(1):55-76
This paper focuses on usability evaluation of information and communication technologies applications in education (ICTE applications).
Various classes of teaching and learning systems are discussed in terms of technologies used and pedagogical approaches. Their
usability is analyzed according to various dimensions and the impact of system usability on the learning effectiveness is
studied. We argue that various classes of ICTE applications such as multimedia/hypermedia applications, open educational environments
and CSCL environments, based on different theoretical perspectives, require fundamentally different approaches in evaluating
their usability. The paper is structured as follows: an overview of different usability evaluation approaches is presented
first, followed by a discussion on applicability of these techniques in various categories of teaching and learning computer
systems. Typical case studies that engage both usability experts and users themselves (students and teachers) are also discussed.
The objective is to describe both the methods, and the way to apply them effectively in order to certify the usability of
an ICTE application with respect to its teaching and learning objectives. 相似文献
38.
Nikolaos K. Tselios Nikolaos M. Avouris Maria Kordaki 《Education and Information Technologies》2002,7(1):17-40
Design and evaluation of computer-based open problem solving environments is a non-trivial task. Definition of a design framework, which involves a strong field-evaluation phase, has been the subject of the research described in this paper. This framework is based on the concept of student task modeling. Tools to support design and evaluation have been built and used in the frame of this study. The framework and the developed tools have produced promising results during the evaluation of an open problem-solving educational environment. 相似文献
39.
Ioannis Kazanidis Nikolaos Pellas Panagiotis Fotaris Avgoustos Tsinakos 《British journal of educational technology : journal of the Council for Educational Technology》2019,50(4):2014-2027
While “flipping” a classroom has gained attention in K-12 and Secondary school programs, there has been relatively no explicit focus on its effectiveness as a teaching method for instructional media design courses in Higher Education. The purpose of this quasi-experimental study was to determine the effectiveness of the flipped classroom approach to teaching instructional media design subjects by comparing students’ academic performance and training satisfaction in traditional lecture-based instruction with those in a flipped classroom. A total of 128 undergraduate students participated voluntarily and were divided into a control (n = 62) and an experimental (n = 66) group, respectively. The study findings indicated substantial differences in both academic performance and training satisfaction between the two groups, with the students in the experimental group performing significantly better. Specifically, the results showed some determining factors associated with training satisfaction that explain why students in flipped classes achieved notably higher mastery in the learning objectives than their control group peers. This study adds to the literature by providing evidence on how a flipped classroom can potentially benefit students’ academic performance, leading to higher training satisfaction and deeper disciplinary understanding in instructional media design courses. 相似文献
40.
The influence of game duration and playing position on intensity of exercise during match-play in elite water polo players 总被引：1，自引：0，他引：1
In this study, we assessed exercise intensity in 20 water polo games of different duration. The hypothesis that right wing players perform at a higher intensity than back and forward central players was also tested. Thirty water polo players, equally split between three field positions, participated in the study. Initially, their performance-related physiological capabilities were evaluated. Subsequently, during water polo games of short (4 x 7-min periods) or long duration (4 x 9-min periods), heart rate was monitored continuously and blood lactate concentration was measured at the end of each period. Activity patterns were also recorded using a video camera. Mean heart rate over the entire game was 156 +/- 18 beats x min(-1). Overall exercise intensity fluctuated around a value corresponding to the lactate threshold (4.03 +/- 0.96 mmol x l(-1), 86 +/- 5% of peak heart rate) and decreased (P < 0.003) with game time (4.22 +/- 1.8 and 3.47 +/- 1.9 mmol x l(-1) in the second and fourth quarter, respectively). During the last 6 min, heart rate was higher (P < 0.001) in games of short duration (156 +/- 3 beats x min(-1)) than in games of long duration (152 +/- 8 beats x min(-1)). Video analysis showed that the percentage of time spent in low-intensity activities (i.e. "out of game") was lower (23 vs. 26%), whereas that in high-intensity activities (i.e. "sprinting crawl") was higher (21 vs. 19%), in games of short compared with long duration. No difference was observed among players of various field positions in any of the variables examined. Thus during match-play, games of long duration produced significantly lower heart rate responses than games of short duration, and the physiological response exhibited by the players was not affected by field position. The water polo authorities should consider these results before changing game duration and coaches should prepare their athletes accordingly. 相似文献