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1.
In recent years there has been widespread interest in the implementation of information and communication technologies (ICT) in schools. While most studies primarily focus on the use of ICT in teaching and learning, little attention has been given to their incorporation as a professional tool outside the classroom. Using a digital inequality approach, the aim of this paper is to develop and test a model of the factors that affect teachers' professional use of ICT, particularly the Internet, in primary and secondary schools. One thousand four hundred and five (1405) teachers from a representative sample of 536 primary and 273 secondary schools in Spain were surveyed. The dependent variables include attitudes towards the professional use of ICT and the use of the Internet in professional practice. The explanatory variables are the socio-demographics, school-level information, frequency of Internet access within and outside the school, educational ICT training, digital literacy, and organisational development. Controlling for socio-demographics and school-level information, multiple regression analyses are used to make inferential judgements and test the separate effects of the independent variables. Findings suggest that technological factors and organisational practices are important predictors of ICT appropriation for professional purposes. 相似文献
2.
Structure–property relationship of sodium deoxycholate based poly(ester ether)urethane ionomers for biomedical applications 下载免费PDF全文
Daniela Filip Doina Macocinschi Stelian Vlad Gabriela Lisa Mariana Cristea Mirela F. Zaltariov 《应用聚合物科学杂志》2016,133(4)
New sodium deoxycholate based poly(ester ether)urethane ionomers were prepared for the development of biomedical materials. A structure–property relationship in the tested biomaterials was established by cross‐examination of the dynamic mechanical and dielectric properties, attenuated total reflection–Fourier transform infrared investigation, thermogravimetric analysis, and surface morphology characterization. A stronger ionic interaction and solvation capacity of the ions and a higher ionic conductivity were manifested in the case of poly(ethylene oxide)‐rich segments than for poly(propylene oxide)‐rich segments in these polyurethane ionomers. The molecular and ionic interactions of the bile‐salt moiety with different polyether cosoft segments influenced chain packing and conformation, supramolecular organization, and the resulting surface morphological microstructures of the polyurethane biomembranes. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42921. 相似文献
3.
Flaviu Tma Rodica Blaa Doina Manu Gabriel Gyorki Rare Chinezu Corina Tma Adrian Blaa 《International journal of molecular sciences》2022,23(3)
Brain metastases represent more than 50% of all cerebral tumors encountered in clinical practice. Recently, there has been increased interest in the study of extracellular vesicles, and the knowledge about exosomes is constantly expanding. Exosomes are drivers for organotropic metastatic spread, playing important roles in the brain metastatic process by increasing the permeability of the blood–brain barrier and preparing the premetastatic niche. The promising results of the latest experimental studies raise the possibility of one day using exosomes for liquid biopsies or as drug carriers, contributing to early diagnosis and improving the efficacy of chemotherapy in patients with brain metastases. In this review, we attempted to summarize the latest knowledge about the role of exosomes in the brain metastatic process and future research directions for the use of exosomes in patients suffering from brain metastatic disease. 相似文献
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This article presents a new classification algorithm, called CLEF, which induces a -machine by constructing its own features based on the training data. The features can be viewed as defining subsets of the instance space, and they allow CLEF to create useful non-linear functions over the input variables. The algorithm is guaranteed to find a classifier that separates the training instances, if such a separation is possible. We compare CLEF empirically to several other classification algorithms, including a well-known decision tree inducer, an artificial neural network inducer, and a support vector machine inducer. Our results show that the CLEF-induced -machines and support vector machines have similar accuracy on the suite tested, and that both are significantly more accurate than the other classifiers produced. We argue that the classifiers produced by CLEF are easy to interpret, and hence may be preferred over support vector machines in certain circumstances. 相似文献
5.
Cristofor I. Simionescu Victor Bulacovschi Doina Macocinschi Gheorghe Stoica Ioan I. Neguiescu 《Polymer Bulletin》1988,19(1):59-63
Summary Suspension type PVC was reacted with sodium phenoxide in presence of different quaternary ammonium halides in THF or THF/water mixtures. The competition elimination vs. substitution of chlorine atoms depends on the homogeneity of the system, i.e. the more homogeneous the reaction mixture the less substituted the polymer.Dedicated to the 60th anniversary of Prof. Otto Vogl 相似文献
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Daniel MARECI Romeu CHELARIU Adrian CAILEAN Florin BRINZA Georgiana BOLAT Doina Margareta GORDIN 《中国有色金属学会会刊》2015,(1):345-353
比较了未再结晶和再结晶Ti12Mo5Ta合金、未再结晶Ti12Mo合金和工业用纯钛(cp-Ti)在0.9%生理盐水(pH 2.3)中37°C下的电化学行为。从阳极极化曲线中得到了极低的钝化电流密度(10-6 A/cm2),这表明所有样品在酸性0.9%NaCl溶液中具有高的耐蚀性能。采用扫描电子显微镜(SEM)观察样品的表面形貌,发现所有样品表面受到了相同的腐蚀,而且经阳极动电位极化测试后的样品表面没有出现点蚀、裂纹或其它缺陷。使用等效电路模拟电化学阻抗谱(EIS)数据,以表征样品表面且更好地理解Mo和Ta的添加对cp-Ti及再结晶的影响。EIS结果证实,在开路电位下,所有样品在0.9%NaCl溶液(pH 2.3)中产生钝化(极化电阻约为105Ω·cm2)。在37°C时,样品在0.9%NaCl溶液中(pH 2.3)的耐蚀性顺序为:再结晶Ti12Mo5Ta未再结晶Ti12Mo5Ta未再结晶Ti12Mocp-Ti。 相似文献
8.
Mona Cioroiu Doina Tarcau Simona Cucu-Man Maria Luca 《The Science of the total environment》2010,408(13):2639-3002
Assessment of organochlorine pesticides (OCPs) in human body is important for human health because they have weak estrogenic or antiestrogenic effects and are considered endocrine disrupters. We used colostrum of women as indicator for levels of OCPs in human body for mothers with normal and preterm labor from eastern part of Romania. Sixty- three samples of colostrum were extracted by solid-phase extraction. Analyses were carried out using gas chromatography coupled to mass spectrometry (GC-MS). OCPs have been detected in all samples, with p,p’-dichlorodiphenyldichloroethylene (p,p’-DDE) and γ-hexachlorocyclohexane (γ-HCH) being at the highest concentrations. Of the organochlorines measured in clostrum samples from women in preterm labor, median levels of DDTs (470 ng/g) and HCHs (99 ng/g) were higher than for the same compounds from women in normal labor (median of DDTs = 268 ng/g and median of HCHs = 96 ng/g). Normal labor had higher median concentrations of HCB (19.5 ng/g) versus preterm labor (14 ng/g). Statistical data show high Spearman correlation coefficients between various OCPs. We found a good correlation between α-, γ-, β- and δ- HCH isomers (p < 0.001) for both normal and preterm labor. The most abundant target compound was p,p’-DDE (median value 96 ng/g, and 137 ng/g for mother with normal and preterm labor, respectively) in all colostrum samples. The estimated daily intakes of HCHs by infants exceeded corresponding Health Canada guidelines. 相似文献
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Ecaterina Andronescu Maria Ficai Georgeta Voicu Denisa Ficai Maria Maganu Anton Ficai 《Journal of materials science. Materials in medicine》2010,21(7):2237-2242
Our purpose was obtaining and characterizing a complex composite system with multifunctional role: bone graft material and
hyperthermia generator necessary for bone cancer therapy. The designed system was a magnetite enriched collagen/hydroxyapatite
composite material, obtained by a co-precipitation method. Due to the applied electromagnetic field the magnetite will induce
hyperthermia and cause tumoral cell apoptosis. The complex bone graft system was characterised by XRD, FTIR and SEM, while
the hyperthermia was quantify by measuring the temperature increase due to the applied alternative electromagnetical field. 相似文献