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201.
202.
Schlotz Wolff; Yim Ilona S.; Zoccola Peggy M.; Jansen Lars; Schulz Peter 《Canadian Metallurgical Quarterly》2011,23(1):80
There is accumulating evidence that individual differences in stress reactivity contribute to the risk for stress-related disease. However, the assessment of stress reactivity remains challenging, and there is a relative lack of questionnaires reliably assessing this construct. We here present the Perceived Stress Reactivity Scale (PSRS), a 23-item questionnaire with 5 subscales and 1 overall scale, based on an existing German-language instrument. Perceived stress reactivity and related constructs were assessed in N = 2,040 participants from the United Kingdom, the United States, and Germany. The 5-factor structure of the PSRS was found to be similar in the 3 countries. In the U.S. sample the questionnaire was applied using 2 modes of administration (paper–pencil and computerized), and measures were repeated after 4 weeks. Measurement invariance analyses demonstrated full invariance across mode of administration and partial invariance across gender and countries. Scale scores differed between countries and genders, with women scoring higher on most scales. Overall, reliability analysis suggested good stability of PSRS scores over a 4-week period, and validation analysis showed expected associations with related constructs such as self-efficacy, neuroticism, chronic stress, and perceived stress. Perceived stress reactivity was also associated with depressive symptoms and sleep. These associations were particularly strong when individuals scoring high on perceived stress reactivity were exposed to chronic stress. In sum, our findings suggest that the PSRS is a useful and easy-to-administer instrument to assess perceived stress reactivity. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
203.
Eveliina Takasuo Stefan Holmström Tuomo Kinnunen Pekka H. Pankakoski Ensio Hosio Ilona Lindholm 《Nuclear Engineering and Design》2011,241(4):1196-1205
The coolability of ex-vessel core debris is an important issue in the severe accident management strategy of, e.g. the Nordic boiling water reactors. In a core melt accident, the molten core material is expected to discharge into the containment and form a porous debris bed on the pedestal floor of a flooded lower drywell. The debris bed generates decay heat which must be removed by boiling in order to stabilize the debris bed and to prevent local dryout and possible re-melting of the material. The STYX test facility which consists of a cylindrical bed of irregular alumina particles has been used to investigate the effect of lateral coolant inflow on the dryout heat flux of the particle bed. The lateral flow was achieved by downcomers attached on the sides of the test rig. The downcomers provide coolant into the lower region of the bed by natural circulation. Both homogenous and stratified bed configurations have been examined. It was observed that the dryout heat flux is increased by 22-25% for the homogenous test bed compared to the case with no lateral flooding. For the stratified configuration with a fine particle layer on top of the bed, no significant increase in the dryout heat flux was observed. The experiments have been analyzed by using the MEWA-2D code. Models which include explicit consideration of gas-liquid friction were used in the calculations in order to realistically capture the lateral flow configuration. 相似文献
204.
Denis Panaitescu Florin Ciuprina Michaela Iorga Adriana Frone Constantin Radovici Marius Ghiurea Serban Sever Ilona Plesa 《应用聚合物科学杂志》2011,122(3):1921-1935
Polymers filled with inorganic nanoparticles have become interesting materials as dielectrics because of their improved mechanical and electrical properties compared with the unfilled polymers and with polymer microcomposites. These improvements are mainly due to the large surface area of nanoparticles and new polymer–nanofiller interface characteristics. In the present work, polyethylene nanocomposites with SiO2 and Al2O3 nanoparticles were prepared by melt mixing. Mechanical and electrical properties of these composites were determined and morphological aspects were revealed by scanning electron microscopy, wide‐angle X‐ray diffraction, and atomic force microscopy. The effect of nanostructure and the importance of nanofiller dispersion were analyzed in connection with mechanical and electrical properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
205.
Imre Bertóti Ilona MohaiMiklós Mohai János Szépvölgyi 《Diamond and Related Materials》2011,20(7):965-968
Commercial multiwall carbon nanotubes (MWCNT-s) were treated by RF activated N2 gas plasma at (nominally) room temperature. Treatment time of 5 to 10 min was applied at negative bias varying in the 0-300 V range. Surface chemical alterations were followed by X-ray photoelectron spectroscopy (XPS). All the applied treatments resulted in a significant build-up of nitrogen in the surface of MWCNT-s. The amount of nitrogen varied between 19 and 25 at.% depending on the treatment time and, in a lesser extent, also on biasing conditions. Interestingly, the nitrogen attachment was also significant (20 at.%) when the treatment commenced without bias. Evaluating the high-resolution N1s XP spectral region, typically three different chemical bonding states of the nitrogen was delineated. Peak component at 398.3 ± 0.3 eV is assigned to CNC type, at 399.7 ± 0.3 eV to sp2 N in melamine-type ring structure and at 400.9 ± 0.3 eV to N substituting carbon in a graphite-like environment. Identical chemical bonding of the nitrogen was detected on the surface of highly oriented pyrolytic graphite (HOPG) and on microcrystalline graphite surfaces treated in the same way for comparison. Estimating the penetration depth of the nitrogen atoms by the SRIM program it was concluded that at the applied DC bias energy range the implanted nitrogen is incorporated in the top 2-4 monoatomic layers of the samples. A model for the distribution of the chemically bonded nitrogen on the outer walls of the MWCNT-s is proposed. 相似文献
206.
Mariana PeredaGuillermina Amica Ilona RáczNorma E. Marcovich 《Journal of food engineering》2011,103(1):76-83
Films made from sodium caseinate and nanocellulose were prepared by dispersing the fibrils into film forming solutions, casting and drying. Composite films were less transparent and had a more hydrophilic surface than neat sodium caseinate ones. However, the global moisture uptake was almost not affected by filler concentration. Addition of nanocellulose to the neat sodium caseinate films produced an initial increase in the barrier properties to water vapor, and then, it decreases as filler content increased. This was explained in terms of additional detrimental changes (cracks and bubble formation) induced in the morphological structure of the film by the reinforcement.The tensile modulus and strength of composite films increased significantly with increasing cellulose concentrations, while the values of elongation decreased. In the same way it was found that the storage modulus increases considerably with filler addition in the low temperature range (<60 °C), though the effect of temperature on the films performance is even more dramatic, as expected in protein-based materials. 相似文献
207.
Maurizio Servili Sonia EspostoGianluca Veneziani Stefania UrbaniAgnese Taticchi Ilona Di MaioRoberto Selvaggini Beatrice SordiniGianFrancesco Montedoro 《Food chemistry》2011
Olive-vegetation water (OVW) is very rich in phenols, which can cause pollution problems, due to their high hydrophilicity and antimicrobial activity. In this study, a three-phase membrane system was applied for the recovery of hydrophilic phenols from fresh OVW in an industrial plant, through a prior enzymatic treatment. This innovation yielded both a crude phenolic concentrate (CPC) and a very high reduction in OVW pollution. Furthermore, the CPC was utilised in a virgin olive oil (VOO) extraction process with the aim of improving VOO phenolic content. The results obtained with four different olive cultivars showed that the CPC extraction increased the phenolic content of the VOOs without any alteration of their aroma profiles. 相似文献
208.
Ingrida Tumosien Ilona Jonukien Kristina Kantminien Vytautas Mickevi
ius Vilma Petrikait 《International journal of molecular sciences》2021,22(15)
A series of novel mono and bishydrazones each bearing a 2-oxindole moiety along with substituted phenylaminopropanamide, pyrrolidin-2-one, benzimidazole, diphenylmethane, or diphenylamine fragments were synthesized, and their anticancer activities were tested by MTT assay against human melanoma A375 and colon adenocarcinoma HT-29 cell lines. In general, the synthesized compounds were more cytotoxic against HT-29 than A375. 3-((4-Methoxyphenyl)(3-oxo-3-(2-(2-oxoindolin-3-ylidene)hydrazinyl)propyl)amino)-N′-(2-oxoindolin-3-ylidene)propanehydrazide and (N′,N‴)-1,1′-(methylenebis(4,1-phenylene))bis(5-oxo-N′-(2-oxoindolin-3-ylidene)pyrrolidine-3-carbohydrazide) were identified as the most active compounds against HT-29 in 2D and 3D cell cultures. The same compounds showed the highest antioxidant activity among the synthesized compounds screened by ferric reducing antioxidant power assay (FRAP). Their antioxidant activity is on par with that of a well-known antioxidant ascorbic acid. 相似文献
209.
Mora-Seró I Bisquert J Fabregat-Santiago F Garcia-Belmonte G Zoppi G Durose K Proskuryakov Y Oja I Belaidi A Dittrich T Tena-Zaera R Katty A Lévy-Clément C Barrioz V Irvine SJ 《Nano letters》2006,6(4):640-650
Four different types of solar cells prepared in different laboratories have been characterized by impedance spectroscopy (IS): thin-film CdS/CdTe devices, an extremely thin absorber (eta) solar cell made with microporous TiO2/In(OH)xSy/PbS/PEDOT, an eta-solar cell of nanowire ZnO/CdSe/CuSCN, and a solid-state dye-sensitized solar cell (DSSC) with Spiro-OMeTAD as the transparent hole conductor. A negative capacitance behavior has been observed in all of them at high forward bias, independent of material type (organic and inorganic), configuration, and geometry of the cells studied. The experiments suggest a universality of the underlying phenomenon giving rise to this effect in a broad range of solar cell devices. An equivalent circuit model is suggested to explain the impedance and capacitance spectra, with an inductive recombination pathway that is activated at forward bias. The deleterious effect of negative capacitance on the device performance is discussed, by comparison of the results obtained for a conventional monocrystalline Si solar cell showing the positive chemical capacitance expected in the ideal IS model of a solar cell. 相似文献
210.
Stern E Jay S Bertram J Boese B Kretzschmar I Turner-Evans D Dietz C LaVan DA Malinski T Fahmy T Reed MA 《Analytical chemistry》2006,78(18):6340-6346
A critical shortcoming of current surface functionalization schemes is their inability to selectively coat patterned substrates at micrometer and nanometer scales. This limitation prevents localized deposition of macromolecules at high densities, thereby restricting the versatility of the surface. A new approach for functionalizing lithographically patterned substrates that eliminates the need for alignment and, thus, is scalable to any dimension is reported. We show, for the first time, that electropolymerization of derivatized phenols can functionalize patterned surfaces with amine, aldehyde, and carboxylic acid groups and demonstrate that these derivatized groups can covalently bind molecular targets, including proteins and DNA. With this approach, electrically conducting and semiconducting materials in any lithographically realizable geometry can be selectively functionalized, allowing for the sequential deposition of a myriad of chemical or biochemical species of interest at high density to a surface with minimal cross-contamination. 相似文献