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1.
Aqueous solutions of poly(vinyl pyrrolidone)-fullerene complexes (PVP-C70) have been studied using static and dynamic light scattering methods. Two diffusive processes were detected. The slow diffusion was interpreted as dynamics of large intermolecular PVP-C70 complexes while the fast diffusion was associated with the presence of individual PVP molecules in solution. It was also shown that the molecular weights and dimensions of PVP-C70 complexes are smaller than for PVP-C60 by a factor of 2.5-3. In aqueous solutions of PVP-C70 complex the depolarization and dissymmetry of scattered light were observed in contrast to PVP-C60 solutions. It reveals the existence of anisotropic structures in PVP-C70 solutions. Intermolecular interactions within PVP-C70 complexes are weak and a hydrodynamic field can destroy complexes. 相似文献
2.
J Hellman EM Zanzot PM Loiselle SF Amato KM Black Y Ge JT Kurnick HS Warren 《Canadian Metallurgical Quarterly》1997,176(5):1260-1268
The binding of IgG in antiserum to Escherichia coli J5 to the surface of Enterobacteriaceae and to cell wall fragments released from serum-exposed bacteria was studied in a search for potentially protective epitopes other than lipopolysaccharide (LPS). IgG titers to multiple heterologous gram-negative smooth bacteria increased following incubation of the bacteria in serum and decreased following absorption with serum-exposed heterologous bacteria. IgG eluted from absorbing bacteria bound to at least three conserved bacterial outer membrane proteins (OMPs), but not LPS, as assessed by immunoblotting. The same OMPs were present in LPS-containing macromolecular cell wall fragments released by incubation of heterologous gram-negative bacteria in human serum. Part of the protection offered by J5 antiserum could be from binding of IgG to conserved OMPs at the bacterial surface or to OMPs in cell-wall fragments released from dying bacteria. 相似文献
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5.
Heikki Hämmäinen Eero Eloranta Esko Pohjanpalo 《Journal of Intelligent Manufacturing》1990,1(4):203-215
Flexible integration of distributed design and manufacturing activities is one of the key issues in applying just-in-time principles along the logistics chain. The potential of AI based approaches in this field is clear, but the inherent asynchrony, concurrency, and inconsistency of distributed operations has reduced enthusiasm so far.This paper discusses coordination in the context of geographically distributed manufacturing of one-of-a-kind products. Cooperation of partners is based on semi-automated user agents which operate as an integrative layer between more dedicated tools and systems. The management of order changes in elevator manufacture is used as a case example.The work reported here is part of the DIMUN project (DIMUN, 1989) in the RACE program. 相似文献
6.
Bonny K. Larsson Heikki Pyysalo Marketta Sauri 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1988,187(6):546-551
Zusammenfassung Es wird über ein Verfahren zur Abtrennung der in gegrillten und geräucherten Lebensmitteln enthaltenen mutagenen polycyclischen organischen Stoffe in einzelne Klassen berichtet. Das Verfahren umfaßt eine erste Extraktion mit Aceton, das Abscheiden von Fett und Proteinen durch Ausfällung bei –55 °C und eine Säure-Base-Extraktion. Die weitere Fraktionierung erfolgte durch Gelfiltration und Silicagel-Chromatographie. Bei vier Proben von gegrillten Würsten waren 80 bis 90% der extrahierten Mutagenität (TA98 + S9) in den basischen Fraktionen enthalten. Die in der Flamme gegrillten Würste hatten eine höhere Mutagenität als die auf Holzkohle gegrillten. Bei den geräucherten Fischen war die Mutagenität gering und verteilte sich gleichmäßig auf die basischen und die neutralen/sauren Fraktionen. Einige Proben zeigten schwache Direktmutagenität in den neutralen/sauren Fraktionen. Die Anwesenheit von Nitrit in den gegrillten Würsten hatte keinen erheblichen Einfluß auf die Mutagenität. Die Gaschromatographie, Selektive Ionregistrierung-Technik, wurde erfolgreich zur Identifizierung mehrerer PAH-Verbindungen eingesetzt, und mit ihr konnten mehrere Nitro-PAH und oxydierte Verbindungen vorläufig identifiziert werden. Der Nachweis der Mutagene in den basischen Fraktionen gestaltete sich jedoch wegen Peak-Schweifbildung und mit-eluierenden Materials kompliziert.Summary A method for class separation of mutagenic polycyclic organic material in grilled and smoked foods is described. The procedure involves an initial extraction with acetone, removal of fat and proteins by precipitation at –55 °C, and an acid-base extraction. Further fractionation was carried out by gel filtration and silica gel chromatography. In four samples of grilled sausages, 80%–90% of the extracted mutagenicity (TA98 + S9) was contained in the basic fractions. Flame-grilled sausages showed higher mutagenicity than charcoal-grilled ones. In a smoked fish sample, the mutagenicity was low and evenly distributed between the basic and the neutral/acidic fractions. A few samples showed a weak direct-acting mutagenicity in the neutral/acidic fractions. The presence of nitrite in grilled sausages did not influence the mutagenicity markedly. Gas chromatography-selected ion monitoring was used to successfully identify a number of polycyclic aromatic hydrocarbons (PAHs) and tentatively identify several nitro-PAHs and oxygenated compounds. However, the identification of mutagens in the basic fractions was complicated by peak tailing and the presence of co-eluting material.
Abtrennung mutagenen polycyclischen organischen Materials in gegrillten und geräucherten Lebensmitteln相似文献
7.
Pekka Manninen Päivi Laakso Heikki Kallio 《Journal of the American Oil Chemists' Society》1995,72(9):1001-1008
This study demonstrates the usefulness of capillary supercritical fluid chromatography (SFC) for the characterization of triacylglycerols
of edible oils and fats. Triacylglycerols were separated according to the acyl carbon number and the degree of unsaturation
on a 25% cyanopropyl/25% phenyl/50% methylpolysiloxane stationary phase. Valuable information concerning the triacylglycerol
composition of berry oils was obtained, despite the overlapping of certain triacylglycerol peaks. Simultaneous analysis of
fat-soluble vitamins and triacylglycerols is not practical by capillary SFC with flame-ionization detection because of the
low concentration of naturally-occurring fat-soluble vitamins in edible oils. Therefore, higher loading of the sample, which
led to overloading of triacylglycerols, was required to get reasonable peaks for fat-soluble vitamins. The method was applied
to the characterization of triacylglycerols and tocopherols in sea buckthorn pulp and seed oil, and cloudberry seed oil without
any sample purification prior to SFC. In addition, the stationary phase proved useful for separating the more complex mixtures
of triacylglycerols found in milk fat and in fish oil. 相似文献
8.
Heikki Srkel Jari Takatalo Patrick May Mikko Laakso Gte Nyman 《International journal of human-computer studies》2009,67(9):787-799
Human movement in virtual environments (VEs) is a largely unstudied area, and there are no well-established methods of measuring it in VEs. Consequently, it is unclear how movement affects the experiential side of VEs. We introduce a novel method of measuring and modelling human movement. A specific information entropy-based modelling method enabled us to identify different movement patterns and analyse the experiential components related to them. The data was collected by registering the movement patterns of 68 participants who were in a virtual house doing a search task. The experiential side of the VE was measured with the Experimental Virtual Environment Questionnaire (EVEQ). Four movement patterns were identified. In addition, fluent movement in VEs was related to a high sense of presence. Moreover, the participants who moved fluently in the environment assessed their skills high. The results show how movement is related the way in which people experience the VE. The movement analysis method introduced here is applicable to other related research areas as well. 相似文献
9.
Calorimetry offers a direct measurement of thermodynamic properties of materials, including information on the energetics of phase transitions. Many materials can only be prepared in thin film or small crystal (submilligram) form, negating the use of traditional bulk techniques. The use of micromachined, membrane-based calorimeters for submilligram bulk samples is detailed here. Numerical simulations of the heat flow for this use have been performed. These simulations describe the limits to which this calorimetric technique can be applied to the realm of small crystals (1-1000 microg). Experimental results confirm the feasibility of this application over a temperature range from 2 to 300 K. Limits on sample thermal conductivity as it relates to the application of the lumped and distributed tau 2 models are explored. For a typical sample size, the simulations yield 2.5% absolute accuracy for the heat capacity of a sample with thermal conductivity as low as 2 x 10(-5) W/cm K at 20 K, assuming a strong thermal link to the device. Silver paint is used to attach (both thermally and physically) the small samples; its heat capacity and reproducibility are discussed. Measurements taken of a submilligram single crystal of cobalt oxide (CoO) compare favorably to the results of a bulk calorimetric technique on a larger sample. 相似文献
10.
Jia M Souchelnytskyi N Hellman U O'Hare M Jat PS Souchelnytskyi S 《Proteomics. Clinical applications》2010,4(10-11):816-828