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排序方式: 共有2543条查询结果,搜索用时 15 毫秒
41.
Measurements of OVOCs and NMHCs in a Swiss highway tunnel for estimation of road transport emissions 总被引:1,自引:0,他引:1
Legreid G Reimann S Steinbacher M Staehelin J Young D Stemmler K 《Environmental science & technology》2007,41(20):7060-7066
Eighteen oxygenated volatile organic compounds (OVOCs) and eight nonmethane hydrocarbons (NMHCs) were measured continuously during a two-week campaign in 2004 in the Gubrist highway tunnel (Switzerland). The study aimed to estimate selected OVOC and NMHC emissions of the current vehicle fleet under highway conditions. For the measured OVOCs the highest EFs were found for ethanol (9.7 mg/km), isopropanol (3.2 mg/km), and acetaldehyde (2.5 mg/km), followed by acetone, benzaldehyde, and acrolein. Formaldehyde, the most abundant OVOC measured in other studies, was not measured by the method applied. Relative emissions of the measured OVOCs were estimated to contribute approximately 6 and 4% to the total road traffic VOC emissions from Switzerland and Europe, respectively. Results are compared with those from previous studies from the same tunnel performed in 1993 and 2002, and from campaigns in other tunnels. A continuous reduction in the emission factors (EFs) was determined for all measured compounds from 1993 until 2004. The relative contributions of light-duty vehicles (LDV) and heavy-duty vehicles (HDV) to the total emissions indicated that OVOCs were mainly produced by the HDVs, whereas LDVs dominated the production of the NMHCs. 相似文献
42.
Arthur Koedam Johannes J. C. Scheffer Anders Baerheim Svendsen 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1979,168(2):106-111
Summary The influence of the time of distillation on the composition of the essential oils isolated from seed of ajowan, caraway, coriander, and cumin was investigated. The oils were isolated by distillation, as well as by simultaneous distillation-extraction. It was observed that the order of recovery of the oil constituents was determined by their solubility in the distillation water. Hence, the oxygenated compounds, although with higher boiling points, distilled before the hydrocarbons. In comparison, data are included for the oils obtained by solvent extraction from ground seed of the same species. In these cases the proportion of hydro carbons was higher than in the distilled oils. There was also evidence to suggest thatp-cymene in the oils of ajowan and cumin was partly an artefact of distillation.
Part I: Chem. Mikrobiol. Technol. Lebensm. (in press) 相似文献
Vergleich von Isolierungsverfahren ätherischer ÖleII. Ajowan, Künunel, Koriander und Kreuzkümmel
Zusammenfassung Der Einfluß der Destillationsäuer auf die Zusammensetzung der ätherischen Öle von Ajowan, Kümmel, Koriander und Kreuzkümmel wurde untersucht. Die Öle wurden sowohl durch Destillation als auch durch ein Destillation-Extraktionsverfahren isoliert. Es wurde gezeigt, daß die Reihenfolge der Ölbestandteile während der Destillation bestimmt wurde von ihrer Löslichkeit im Destillationswasser, weshalb die höher siedenden sauerstoffhaltigen Komponenten schneller als die Kohlenwasserstoffe übergehen.Zum Vergleich wurden Angaben aufgenommen für Öle, die mit organischen Lösungsmitteln aus gemahlenen Früchten extrahiert worden waren. In diesen Fällen war die Menge der Kohlenwasserstoffe höher als bei den destillierten Ölen. Es gibt Hinweise dafür, daßp-Cymol in Ajowan- und Kreuzkümmelöl teilweise ein Artefakt der Destillation ist.
Part I: Chem. Mikrobiol. Technol. Lebensm. (in press) 相似文献
43.
Jacob B. Buntjer Johannes A. Lenstra Nel Haagsma 《European Food Research and Technology》1995,201(6):577-582
A fast procedure for species identification in heated meat is described. Deoxyribonucleic acid (DNA) was isolated from meat samples by an alkaline extraction method and hybridized to a conjugate of a specific oligonucleotide and alkaline phosphatase. The oligonucleotide probes are based on satellite DNA, tandem-repeated sequences, which are highly specific for species. Probes are developed for the identification of meat from cattle, sheep/goat, horse, deer, pig, chicken and turkey. Differentiation between closely related species like chicken and turkey is possible. Admixtures of 1–5% of meat of one species in another could be detected. The complete assay of up to 50 samples takes 4 h. Heated meat samples could be analysed. 相似文献
44.
Amanda M Teekens Marieke E Bruins Johannes MN van Kasteren Wouter H Hendriks Johan PM Sanders 《Journal of the science of food and agriculture》2016,96(8):2603-2612
Processing biomass into multi‐functional components can contribute to the increasing demand for raw materials for feed and bio‐based non‐food products. This contribution aims to demonstrate synergy between the bio‐based industry and the feed industry through biorefinery of currently used feed ingredients. Illustrating the biorefinery concept, rapeseed was selected as a low priced feed ingredient based on market prices versus crude protein, crude fat and apparent ileal digestible lysine content. In addition it is already used as an alternative protein source in diets and can be cultivated in European climate zones. Furthermore, inclusion level of rapeseed meal in pig diet is limited because of its nutritionally active factors. A conceptual process was developed to improve rapeseeds nutritional value and producing other bio‐based building blocks simultaneously. Based on the correlation between market prices of feed ingredients and its protein and fat content, the value of refined products was estimated. Finally, a sensitivity analysis, under two profit scenario, shows that the process is economically feasible. This study demonstrates that using biorefinery processes on feed ingredients can improve feed quality. In conjunction, it produces building blocks for a bio‐based industry and creates synergy between bio‐based and feed industry for more efficient use of biomass. © 2015 Society of Chemical Industry 相似文献
45.
A commercially available PCR kit (AnDiaTec Salmonella sp. PCR-ELISA) was developed and evaluated for the detection of Salmonella sp. in food samples. The test is based on PCR amplification and hybridization of the amplified DNA to a microtiter plate followed by the detection of PCR product in the manner of an enzyme-linked immunosorbent assay test. The sensitivity and specificity were evaluated first with Salmonella pure cultures and artificially contaminated food samples, including food types for which an inhibition of the PCR reaction was expected. Both experiments proved a very good sensitivity, specificity, and reliability of the test with a very broad range of food types. In a second evaluation study, more than 1,100 food samples of different types were tested in parallel with the PCR method and with the International Standardization Organization 6579 bacteriological reference method. The results of this evaluation study and the results from other experiments on dilutions of artificially contaminated food samples led to the establishment of a positive-negative cutoff value (optical density at 450 nm of more than 0.9) with respect to the conventional bacteriological method. Using this positive-negative cutoff, 98% agreement to the bacteriological method was obtained. 相似文献
46.
47.
48.
Umberto De Rossi Johannes Moll Monika Spieles Günther Bach Siegfried Dhne Jrg Kriwanek Maria Lisk 《Advanced Synthesis \u0026amp; Catalysis》1995,337(1):203-208
Cyanine dyes ( 1a–d ) with the 5,5′,6,6′-tetrachloro-1,1′-dialkyl-3,3′-di-(3-carboxypropyl)-benzimidocarbocyanine chromophore differing only in the chain length of their alkyl groups in 1,1′-position have been synthesized, spectroscopically characterized, and compared with 5,5′6,6′-tetrachloro-1,1′-diethyl-3,3′-di-(4-sulfobutyl)-benzimidocarbocyanine( TDBC ). In aqueous solution the dyes form J-aggregates which, depending on the alkyl group chain length, exhibit J-bands differing in spectral positions, bandwidth, and in the number of peaks. 相似文献
49.
50.
Alexandre Joushomme Andr Garenne Mlody Dufosse Rmy Renom Hermanus Johannes Ruigrok Yann Loick Chappe Anne Canovi Lorenza Patrignoni Annabelle Hurtier Florence Poulletier de Gannes Isabelle Lagroye Philippe Lvêque Noëlle Lewis Muriel Priault Delia Arnaud-Cormos Yann Percherancier 《International journal of molecular sciences》2022,23(2)
It remains controversial whether exposure to environmental radiofrequency signals (RF) impacts cell status or response to cellular stress such as apoptosis or autophagy. We used two label-free techniques, cellular impedancemetry and Digital Holographic Microscopy (DHM), to assess the overall cellular response during RF exposure alone, or during co-exposure to RF and chemical treatments known to induce either apoptosis or autophagy. Two human cell lines (SH-SY5Y and HCT116) and two cultures of primary rat cortex cells (astrocytes and co-culture of neurons and glial cells) were exposed to RF using an 1800 MHz carrier wave modulated with various environmental signals (GSM: Global System for Mobile Communications, 2G signal), UMTS (Universal Mobile Telecommunications System, 3G signal), LTE (Long-Term Evolution, 4G signal, and Wi-Fi) or unmodulated RF (continuous wave, CW). The specific absorption rates (S.A.R.) used were 1.5 and 6 W/kg during DHM experiments and ranged from 5 to 24 W/kg during the recording of cellular impedance. Cells were continuously exposed for three to five consecutive days while the temporal phenotypic signature of cells behavior was recorded at constant temperature. Statistical analysis of the results does not indicate that RF-EMF exposure impacted the global behavior of healthy, apoptotic, or autophagic cells, even at S.A.R. levels higher than the guidelines, provided that the temperature was kept constant. 相似文献