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Anna Klisi&#x;ska-Kopacz Renata Ti&#x;lova Grzegorz Adamski Roman Koz&#x;owski 《Journal of Cultural Heritage》2010,11(4):950-410
Mercury porosimetry was applied to the study of pore structure of the historic Roman cement mortars representative of different locations in Europe and time periods as well as different application techniques from architectural castings to in situ formed renders and profiles. Three categories of pores were found to coexist in the mortars. The finest pores, with diameters below 0.1 μm, are present within the hardened aged Roman cement matrix. The larger ‘air’ pores, with diameters between 0.2–2 μm, are due to the evaporation of the excess unbound water and restricted hydration. Pores larger than 2 μm are rare and, in general, can be related to microcracking induced by shrinkage drying and mortar weathering. The mortars have rarely been found to develop a dense fine-porous microstructure characteristic of the ideal conditions of moist-curing; massive architectural castings being the only exception identified. The presence of larger ‘air’ pores was, in turn, almost universally observed. The investigations of the freshly prepared Roman cement mortars have revealed that the restricted hydration could be due to the exposure of the freshly laid surface to dry real-world external environments, a high water-to-cement ratio in the original mortars, or the drawing of water from the stucco mass due to insufficient pre-wetting of the porous masonry. The insufficient reactivity of historic cements, resulting from a high content of over-burned, non-reactive cement components or coarseness of the cement grains, could be another reason for yielding poorly hydrated mortars in the past. In general, Roman cement stuccoes are in an excellent state of preservation in spite of their usual exposure to polluted urban environments for more than a century. Therefore, the coexistence of Roman cement mortars of widely different pore structures has not brought about any problems of incompatibility which field observations could reveal. The Roman cement repair materials have been found to develop pore structures similar to those of historic mortars. Therefore, they are in broad terms compatible with historic masonry or stuccoes. However, the porosity and strength of the repair materials can be controlled by a careful manipulation of the water-to-cement ratio of the mix to adapt them better to the properties of the host material. 相似文献
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We investigated relationships between students’ perceptions of parental involvement in schooling, their Spanish classroom environment and student outcomes (attitudes and achievement). Modified Spanish versions of the What Is Happening In this Class?, Test of Spanish-Related Attitudes-L1, a parental involvement questionnaire and a Spanish achievement test were administered to 223 Hispanic Grade 4–6 students in South Florida. The factor structure and internal consistency reliability of the questionnaires was supported. Strong associations were found for parental involvement with students’ learning environment perceptions and student outcomes, and for Spanish classroom environment with student outcomes. When the unique and common variances in student outcomes explained by the classroom environment and the home environment were examined, the home environment was more influential than the classroom environment in terms of students’ attitudes, but the classroom environment was more influential than the home environment in terms of achievement. 相似文献
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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.6.
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7.
A global state feedback tracking controller for a class of vehicles, namely marine vehicles, hovercrafts and indoor airships is considered in this paper. The control algorithm uses a velocity transformation of the vehicle equations of motion. It is shown that this algorithm is suitable for control of fully actuated systems and leads to fast response. This property arises from the fact that the dynamical couplings in the vehicle are taken into account in the control gain matrix. A Lyapunov-like function is proposed for the stability analysis of the system under the controller. The algorithms robustness issue is considered too. Numerical simulations are given to illustrate effectiveness of the approach. 相似文献
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Joanna Smogorzewska Grzegorz Szumski 《International Journal of Disability, Development & Education》2018,65(3):318-340
This study tested whether and how methods called ‘Play Time/Social Time’ and ‘I Can Problem Solve’ contribute to the improvement of social skills and the development of theory of mind (ToM) in children. The participants in the experiment were nearly 200 (N = 196) preschool children with low social functioning, with and without disabilities. The study showed that social skills and the level of ToM in children attending the lessons improved more than those of children from the control group. Both methods turned out to be effective in the case of social skills and ToM development among children with and without disabilities. It is worthwhile to popularise these methods among preschool teachers. 相似文献
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Premadasa Udagama Mirosław Szymański Grzegorz Szumski Kevin M. Lillis J. K. Rooney Dietmar Kahsnitz Emiel Droogleever Fortuijn R. Murray Thomas Lars Mählck N. V. Varghese 《International Review of Education/Internationale Zeitschrift für Erziehungswissenschaft/Revue internationale l'éducation》1989,35(3):365-377
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This paper presents some theoretical and methodological considerations associated with the geographical and professional mobility of science professionals, including the conduct by the authors of a large scale survey questionnaire in Poland in 1994. It does not directly relate to research conducted elsewhere in the region, but does reflect selected issues and problems encountered. 相似文献