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41.
Paweł Fritzkowski Roman Starosta Grażyna Sypniewska-Kamińska Jan Awrejcewicz 《浙江大学学报(A卷英文版)》2017,18(7):497-510
A 1D chain of coupled oscillators is considered, including the Duffing-type nonlinearity, viscous damping, and kinematic harmonic excitation. The equations of motion are presented in a non-dimensional form. The approximate equations for the vibrational amplitudes and phases are derived by means of the classical averaging method. A simple analysis of the resulting equations allows one to determine the conditions for the two basic synchronous steady-states of the system: the in-phase and anti-phase motions. The relations between the required excitation frequency and the natural frequencies of the abbreviated (linear) system are discussed. The validity of these predictions is examined by a series of numerical experiments. The effect of the model parameters on the rate of synchronization is analyzed. For the purpose of systematic numerical studies, the cross-correlation of time-series is used as a measure of the phase adjustment between particular oscillators. Finally, some essential issues that arise in case of the mechanical system with dry friction are indicated. 相似文献
42.
Radosław Wieczór Anna Maria Wieczór Grażyna Gadomska Katarzyna Stankowska Jacek Fabisiak Karol Suppan Grzegorz Pulkowski Jacek Budzyński Danuta Rość 《Journal of Zhejiang University. Science. B》2016,17(11):842-849
Objective
Being overweight or obese comprises a significant risk factor for atherosclerosis. Fat tissue also generates factors stimulating angiogenesis, the process by which new blood vessels form. The purpose of this paper is to assess concentrations of the vascular endothelial growth factor A (VEGF-A) and its soluble type-1 and type-2 receptors (sVEGFR-1 and sVEGFR-2) in plasma of patients with peripheral arterial disease (PAD) depending on the level of nutrition according to body mass index (BMI).Methods
The study group included patients suffering from symptomatic PAD (n=46) in Fontaine classes IIa–IV without any history of neoplastic disease and who have a normal BMI (n=15), are overweight (n=21) or are obese (n=10). The control group (n=30) consisted of healthy non-smoking volunteers who were neither overweight nor obese. Venous blood plasma samples were collected from both groups at rest in the morning to determine plasma concentrations of VEGF-A, sVEGFR-1, and sVEGFR-2 using the enzymelinked immunosorbent assay (ELISA) method.Results
The group of patients with PAD co-existent with being overweight or obese tended to have higher mean concentration levels of VEGF-A and sVEGFR-2 when compared with patients suffering from PAD with normal BMI. A statistically significant positive correlation was obtained between BMI and average plasma concentrations of sVEGFR-2 (R=0.37, P=0.0103). However, no significant correlation was noticed between BMI and VEGF-A or sVEGFR-1 concentrations.Conclusions
A positive correlation determined between the level of antiangiogenic factor and BMI value may be indicative of the linearly growing prevalence of some antiangiogenic factors in patients with metabolic disorders, which may be one of numerous factors contributing to incomplete efficiency of collateral circulation development in patients with PAD.43.
Pawe? Olczyk Katarzyna Komosińska-Vassev Katarzyna Winsz-Szczotka Ewa M. Ko?ma Grzegorz Wisowski Jerzy Stojko Katarzyna Klimek Krystyna Olczyk 《Journal of Zhejiang University. Science. B》2012,13(11):932-941
Objective
This study was aimed at assessing the dynamics of vitronectin (VN), laminin (LN), and heparan sulfate/heparin (HS/HP) content changes during experimental burn healing.Methods
VN, LN, and HS/HP were isolated and purified from normal and injured skin of domestic pigs, on the 3rd, 5th, 10th, 15th, and 21st days following thermal damage. The wounds were treated with apitherapeutic agent (propolis), silver sulfadiazine (SSD), physiological salt solution, and propolis vehicle. VN and LN were quantified using an immunoenzymatic assay and HS/HP was estimated by densitometric analysis.Results
Propolis treatment stimulated significant increases in VN, LN, and HS/HP contents during the initial phase of study, followed by a reduction in the estimated extracellular matrix molecules. Similar patterns, although less extreme, were observed after treatment with SSD.Conclusions
The beneficial effects of propolis on experimental wounds make it a potential apitherapeutic agent in topical burn management. 相似文献44.
Marcelina Łopińska Jerzy Stanisław Gielecki Anna Żurada 《Anatomical sciences education》2022,15(5):886-897
The flipped spotters learning model is a modern student activity-based and learner-centered method in medical education. The aim of the study was to determine if the flipped spotters learning model improves students' learning. Participants were 1214 medical students of Polish (PD) and English (ED) divisions between 2013 and 2019 academic years at the University of Warmia and Mazury in Olsztyn, Poland. They were divided into a traditional group (control group) and a flipped spotters learning group (treatment group). Each flipped spotters learning group was asked to label anatomical structures on various specimens according to the structures name list prepared by the teacher on the multiple stations. The flipped spotters learning group leaders were instructed to take pictures with the appropriately marked structures on each of the human body prosections. After completion of the class, each flipped spotters team received photos for evaluation. In the flipped spotters learning model, the students strengthened their skills and knowledge by matching specimens independently as a form of practical laboratory activities. Students' performance in gross anatomy practical examinations between the group utilizing the flipped spotters learning model, and the group with the traditional teaching model was compared. Students participating in the treatment group achieved, on average 9.9 percentage points higher among PD students, and 13.0 percentage points higher among ED students than the control group in all nine practical examinations (the effect size ranging from 0.47 to 0.95). The results suggest the positive impact of flipped spotters model on improving student's performance in the practical examinations. 相似文献
45.
Rowland Jussara Estevens João Krzewińska Aneta Warwas Izabela Delicado Ana 《Science & Education》2022,31(5):1399-1424
Science & Education - Public trust in science and expertise remains a contentious issue. When public trust is analysed, it often simplifies a complex process of information retrieval and... 相似文献
46.
Łukasz Tomczyk Rene Szotkowski Artur Fabiś Arkadiusz Wąsiński Štefan Chudý Pavel Neumeister 《Education and Information Technologies》2017,22(3):747-767
The paper presents the complex problems of preparation of pedagogy students to work as teachers in the context of their readiness to use ICT in the didactic process. The complexity of this subject matter has been proved by the current, ongoing, discussion about the direction of the expected transformations of contemporary schools and the prospective teachers education system in the age of prevalent digitization. Considering the complexity of conditions, the main research problem has been formulated as follows: Conditions of what type affect the preparation of prospective teachers to use new media in learning and teaching process?. Thus, the empirical analysis conducted in the paper focuses on the following issues: the style of using new media by students, identification of students’ attitudes towards media, subjective (from the students’ point of view) assessment of how university level schools are prepared to shape modern media competences among their students and self-evaluation of media and IT competences in the group of prospective teachers. Czech and Polish students, despite being the so called digital natives, do not present homogeneous styles of using new media. They also reveal different attitudes toward applying digital solutions to the didactic process. Factors such as: low evaluation of one’s own competences or lack of evaluation in this area, lack of creative approach to the use of new media, lack of education in the area of new applications, lack of skills necessary to handle basic digital tools (e.g. interactive board, e-learning platforms) negatively affect, in most cases, the attitude toward the active use of ICT tools in future didactic work. On the basis of the gathered empirical data and inductive qualitative analysis a typology of students attitudes toward new media was developed. It consists of four categories: techno-optimist, techno-realist, techno-pessimist and techno-ignorant. The whole of analyses has the character of comparative research and involves two neighboring countries of the Visegrad Group: Poland (N?=?466) and Czech Republic (N?=?168). 相似文献
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