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排序方式: 共有75条查询结果,搜索用时 15 毫秒
1.
Virtanen Pekka; Rantalaiho Liisa; Koivisto Anna-Maija 《Canadian Metallurgical Quarterly》2003,8(2):123
Medical students entering the labor market were studied to find out whether the improvement of psychosocial well-being depends on characteristics of their careers. Psychosocial well-being was described on the basis of psychosomatic stress symptoms, psychological distress (General Health Questionnaire), and strain resistance resources (Sense of Coherence). The 3-year follow-up showed that among women the improvement of strain resistance resources was delayed in the group with several entries into work. Among men the findings suggested associations between stress symptoms and career characteristics. Most of the results, however, did not support the hypothesis about the division of the participants into those with a stable career and improving well-being and those with a fragmented career and low well-being. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
2.
Marina Heinonen Katri Haila Anna-Maija Lampi Vieno Piironen 《Journal of the American Oil Chemists' Society》1997,74(9):1047-1052
The effects of low concentrations of β-carotene, α-, and γ-tocopherol were evaluated on autoxidation of 10% oil-in-water emulsions
of rapeseed oil triacylglycerols. At concentrations of 0.45, 2, and 20 μg/g, β-carotene was a prooxidant, based on the formation
of lipid hydroperoxides, hexanal, or 2-heptenal. In this emulsion, 1.5, 3, and 30 μg/g of γ-tocopherol, as well as 1.5 μg/g
of α-tocopherol, acted as antioxidants and inhibited both the formation and decomposition of lipid hydroperoxides. Moreover,
at a level of 1.5 μg/g, γ-tocopherol was more effective as an antioxidant than α-tocopherol. At levels of 0.5 μg/g, both α-
and γ-tocopherol significantly inhibited the formation of hexanal but not the formation of lipid hydroperoxides. Oxidation
was effectively retarded by combinations of 2 μg/g β-carotene and 1.5 μg/g γ- or α-tocopherol. The combination of β-carotene
and α-tocopherol was significantly better in retarding oxidation than α-tocopherol alone. While γ-tocopherol was an effective
antioxidant, a synergistic effect between β-carotene and γ-tocopherol could not be shown. The results indicate that there
is a need to protect β-carotene from oxidative destruction by employing antioxidants, such as α- and γ-tocopherol, should
β-carotene be used in fat emulsions. 相似文献
3.
Heinonen Johanna; Aro Tuija; Ahonen Timo; Poikkeus Anna-Maija 《Canadian Metallurgical Quarterly》2011,23(1):184
Test-taking behaviors (i.e., task focus, maintenance of attention, and cooperation) affect children's cognitive test performance, and, thus, it is critical to take test-taking behavior into account when drawing conclusions and making recommendations. Prior studies have evaluated test-taking behaviors at the end of the assessment; the present study focused on the fluctuation of cooperation and attention during a neuropsychological assessment. We examined the attention and cooperation of 5-year-old children in a test-taking situation; the associations between these aspects of their test-taking behavior and the children's concurrent neurocognitive test performance, IQ, and parent-rated behavior; and the associations with their IQ, behavioral outcomes, and academic achievement at 8 years of age. The data (for 76 boys and 63 girls) were drawn from the Jyv?skyl? Longitudinal Study of Dyslexia (Lyytinen et al., 2001, 2004). All the children were Caucasian and spoke Finnish as their native language. As a whole, the 5-year-old children showed high cooperation and attention, but a slight decrement in test-taking behavior toward the end of the session was rather common. Three subgroups of children with different levels of cooperation and attention were identified. Children in the subgroup with nonoptimal attention and cooperation showed decreasing neurocognitive test performance toward the end of the assessment session. They also showed more inattentive behavior 3 years later. The findings imply that the examiner's observations of waning attention and cooperation during the assessment session are highly relevant, as these provide stable and clinically meaningful information about the child's behavioral tendencies. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
4.
Raman spectroscopy of wood and lignin samples is preferably carried out in the near-infrared region because lignin produces an intense laser-induced fluorescence background at visible excitation wavelengths. However, excitation of aromatic and conjugated lignin structures with deep ultra violet (UV) light gives resonance-enhanced Raman signals while the overlapping fluorescence is eliminated. In this study, ultra violet resonance Raman (UVRR) spectroscopy was used to define characteristic vibration bands of model compounds of p-hydroxyphenyl, guaiacyl, and syringyl lignin structures at three excitation wavelengths (229, 244, and 257 nm). The intensities of each band, relative to the intensity of the aromatic vibration band at 1600 cm-1, were defined and the most suitable excitation wavelength was suggested for each structure. p-Hydroxyphenyl structures showed intensive characteristic bands at 1217-1214 and 1179-1167 cm-1 with excitation at 244 nm, whereas the bands of guaiacyl structures were more intensive with 257 nm excitation. Most intensive characteristic bands of guaiacyl structures were found at 1289-1279, 1187-1185, 1158-1155, and 791-704 cm-1. Syringyl structures had almost identical spectra with 244 and 257 nm excitations with characteristic bands at 1514-1506, 1333-1330, and 981-962 cm-1. The characteristic bands of the three structural units were also found from the compression wood, softwood, and hardwood samples, indicating that UVRR spectroscopy can be applied for the determination of chemical structures of lignin. 相似文献
5.
The feasibility of security solution for RFID tags relies heavily on its hardware cost and performance. In the literature the term lightweight solution is used liberally and causes problems when selecting a solution for e.g. RFID environment. Evaluating the actually feasibility of the solution requires electrical engineering skills that many security developers and decision makers may lack. In this paper we describe simple guidelines for approximating the feasibility of the security solution in terms of gates and clock cycles. These guidelines make it easier to evaluate the cryptographic solutions feasibility for targeted hardware and provide a basis for categorisation of lightweight security solutions. 相似文献
6.
Dimer formation during the thermo-oxidation of stigmasterol 总被引:1,自引:1,他引:0
Karin Struijs Anna-Maija Lampi Velimatti Ollilainen Vieno Piironen 《European Food Research and Technology》2010,231(6):853-863
The monomeric oxidation products formed during the thermo-oxidation of phytosterols do not explain the loss of unoxidized
phytosterols, leaving a gap in the knowledge on the products that are being formed during thermo-oxidation. Previous research
showed that the gap can be explained by the formation of dimers and polymers. The aim of this research was to investigate
the dimers that are formed during the thermo-oxidation of phytosterols, using stigmasterol as a model compound. Following
the oxidation of stigmasterol at 180 °C, several dimeric fractions were obtained by solid phase extraction and high-performance
size-exclusion chromatography. Individual dimers were separated by reversed-phase high-performance liquid chromatography,
and their molecular masses were determined by combining atmospheric pressure chemical ionization-mass spectrometry and coordination-ion
spray-mass spectrometry. This study resulted, for the first time, in the assignment of several individual stigmasterol dimers.
The most dominant dimer was found to have a molecular mass of 822.7 Da and is suggested to represent a C–C linked dimer of
stigmasterol, in accordance with literature. Several other stigmasterol dimers were found to be formed during thermo-oxidation,
which are suggested to differ in monomeric subunit composition, linkage type, and stereochemistry. 相似文献
7.
Gun Wirtanen Satu Salo Merja Karwoski Anna-Maija Sjöberg 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1995,200(3):194-197
A microbiological screening method for the detection of irradiation of frozen poultry meat was developed on the basis of the combined use of total cell count by the direct epifluorescent filter technique (DEFT) and viable cell count by the aerobic plate count method (APC). Samples of ground, deboned poultry leg were irradiated or not with dose levels of 3, 5 and 7 kGy using an electron beam accelerator. All samples were frozen before the irradiation treatment. The average values of the differences between DEFT and APC counts in control samples and those irradiated with doses of 3, 5 and 7 kGy were 1.14 log units for control samples, and 3.16, 3.68 and 3.79 log units for the irradiated samples. A difference of at least 2 log units can therefore be considered as a limit value indicating probable irradiation treatment necessitating further investigations.
Anwendung eines mikrobiologischen Unterscheidungsverfahrens zum Nachweis der Bestrahlung von gefrorenem Hühnerfleisch
Zusammenfassung Es wurde ein mikrobiologisches Verfahren zum Nachweis der Bestrahlung von tiefgefrorenem Hühnerfleisch auf der Basis kombinierten Einsatzes direkter Epifluoreszenzfiltertechnik (DEFT) und Kolonieauszählung (APC) entwickelt. Die Proben - knochenfreie, zerkleinerte Hühnerschenkel - waren entweder unbestrahlt oder mit einem Elektronenbeschleuninger mit Dosen von 3, 5 bzw. 7 kGy bestrahlt worden. Alle Proben waren vor der Bestrahlung eingefroren worden. Die Mittelwerte der Differenzen zwischen den DEFT- und den APC-Ergebnissen betrugen bei den unbestrahlten Proben 1,14 logarithmische Einheiten und bei den mit 3, 5 bzw. 7 kGy bestrahlten Proben 3,16, 3,68 bzw. 3,79 logarithmische Einheiten. Die Differenz von wenigstens zwei logarithmischen Einheiten kann als Grenze für die Möglichkeit eines Nachweises eventueller Bestrahlung betrachtet werden und macht weitere Untersuchungen erforderlich.相似文献
8.
Anna-Maija Sjöberg Pirjo-Liisa Penttilä 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1988,186(3):197-200
Summary The dietary intake of saccharin and cyclamate was investigated during the period 1979–1985 in order to find out about the use as sweeteners in the food industry and hospitals and to obtain intake data for the toxicological evaluation of sweeteners in the Finnisch diet. Eighty-nine samples of desserts served in 85 hospitals were analysed in 1983. Other samples investigated were artificially sweetened commercial foods available in Finland, such as soft drinks, sweets and jellies. The intake evaluation was carried out with reference to the acceptable daily intake (ADI), with commercial portions for a child being 20 kg and for an adult 60 kg. The most important foods with regard to the intake of saccharin and cyclamate were soft drinks. In 1979, 1982 and 1985, soft drinks contributed 128%, 93%, and 51%, respectively, of the ADI of artificial sweeteners for children and 42%, 31%, and 17% for adults. Artificially sweetened desserts served in hospitals contributed to 35% of the ADI for children and 11% for adults.
Die finnischen Lebensmittel als Saccharin-und Cyclamatspender von 1979–1985
Zusammenfassung In den Jahren 1979–1985 wurden finnische Lebensmittel als Saccharin- und Cyclamatspender mit dem Ziel untersucht, den Einsatz von Süßungsmitteln in der Lebensmittelindustrie und in Krankenhäusern zu verfolgen und damit Erkenntnisse über deren toxikologische Wertung in der finnischen Nahrung zu erhalten. Es wurden 89 Proben künstlich gesüßter Nachspeisen aus 85 Krankenhäusern analysiert. Bei den übrigen Proben handelte es sich um in Finnland im Handel befindliche künstlich gesüßte Lebensmittel wie Erfrischungsgetränke, Süßwaren und Konfitüren. Die Schätzung der Zufuhr erfolgte durch Vergleich der täglich zulässigen Menge (ADI), die man aus handelsüblichen Dosen für Kinder von 20 kg Gewicht und Erwachsene von 60 kg Gewicht erhielt. Die wichtigsten Lebensmittel in der Saccharin- und Cyclamat-Zufuhr waren die Erfrischungsgetränke. In den Jahren 1979, 1982 und 1985 entfielen auf Erfrischungsgetränke 128%, 93% bzw. 51% des für Kinder berechneten ADI-Wertes an künstlichen Süßstoffen und entsprechend 42%, 31 % bzw. 17% des für Erwachsene berechneten ADI-Wertes. Die in Krankenhäusern gebotenen künstlich gesüßten Nachspeisen deckten bei Kindern 35% und bei Erwachsenen 11% des ADI-Wertes.相似文献
9.
Laura Soupas Laura Juntunen Suvi Säynäjoki Anna-Maija Lampi Vieno Piironen 《Journal of the American Oil Chemists' Society》2004,81(2):135-141
A new GC-MS method for characterization and quantification of phytosterol oxidation products was developed. Applicability
of this method was tested by characterizing sitostanol oxides formed in bulk and then quantifying selected oxides in purified
rapeseed oil and tripalmitin matrices in which the complex matrix made oxide analysis difficult. In bulk, nine different sitostanol
oxides were characterized, including epimers of 7- and 15-hydroxysitostanol and 6- and 7-ketositostanol. In both lipid matrices,
the amounts of sitostanol oxides generated in thermo-oxidation were very low. According to statistical analyses, depending
on the oxide, the GC-MS results were the same or slightly higher than those quantified by the more common GC-FID method. Thus,
GC-MS provides a powerful alternative for characterization and quantification of phytostanol oxides found in low amounts in
complex matrices and is a promising method for future phytosterol oxide studies. 相似文献
10.
Flax and hemp fibres as raw materials for thermal insulations 总被引:2,自引:0,他引:2
Bast fibres of, for example, flax and hemp are used as raw materials of thermal insulations. However, they have only a minor share in the market. The aim of this paper was to evaluate the suitability of bast fibres of flax and hemp for thermal insulations. The functions and requirements of the bast fibrous insulations and their combustion resistance are discussed. Thermal conductivity and the effects of several parameters on thermal performance are reviewed. The potential and costs of the raw material and quality and ecological aspects are also discussed. Finally, needs for future research is proposed. 相似文献