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排序方式: 共有523条查询结果,搜索用时 15 毫秒
71.
Guinée Jeroen B. Koning Arjan de Pennington David W. Rosenbaum Ralph Hauschild Michael Olsen Stig I. Molander Sverker Bachmann Till M. Pant Rana 《The International Journal of Life Cycle Assessment》2004,9(5):320-326
Goal, Scope and Background The EU 5th framework project OMNIITOX will develop models calculating characterisation factors for assessing the potential toxic impacts
of chemicals within the framework of LCA. These models will become accessible through a web-based information system. The
key objective of the OMNIITOX project is to increase the coverage of substances by such models. In order to reach this objective,
simpler models which need less but available data, will have to be developed while maintaining scientific quality. Methods.
Experience within the OMNIITOX project has taught that data availability and quality are crucial issues for calculating characterisation
factors. Data availability determines whether calculating characterisation factors is possible at all, whereas data quality
determines to what extent the resulting characterisation factors are reliable. Today, there is insufficient knowledge and/or
resources to have high data availability as well as high data quality and high model quality at the same time.
Results The OMNIITOX project is developing two inter-related models in order to be able to provide LCA impact assessment characterisation
factors for toxic releases for as broad a range of chemicals as possible: 1) A base model representing a state-of-the-art
multimedia model and 2) a simple model derived from the base model using statistical tools. Discussion. A preliminary decision
tree for using the OMNIITOX information system (IS) is presented. The decision tree aims to illustrate how the OMNIITOX IS
can assist an LCA practitioner in finding or deriving characterisation factors for use in life cycle impact assessment of
toxic releases.
Conclusions and Outlook Data availability and quality are crucial issues when calculating characterisation factors for the toxicity impact categories.
The OMNIITOX project is developing a tiered model approach for this. It is foreseen that a first version of the base model
will be ready in late summer of 2004, whereas a first version of the simple base model is expected a few months later. 相似文献
72.
Alternaria alternata is a common fungal parasite on fruits and other plants and produces a number of mycotoxins, including alternariol (3,7,9-trihydroxy-1-methyl-6H-dibenzo [b,d]pyran-6-one), alternariol monomethyl ether (3,7-dihydroxy-9-methoxy-1-methyl-6H-dibenzo[b,d]pyran-6-one), and the mutagen altertoxin I {[1S-(1α,12aβ,12bα)] 1,2,11,12,12a, 12b-hexahydro-1,4,9,12a-tetrahydroxy-3,10-perylenedione}.
Alternariol and alternariol monomethyl ether have previously been detected in some samples of fruit beverages. Stability studies
of these toxins as well as altertoxin I added to fruit juices and wine (10–100 ng/mL) were carried out. To include altertoxin
I in the analysis, cleanup with a polymer-based Varian Abselut solid phase extraction column was used, as recoveries from
C-18 columns were low. The stabilities of alternariol and alternariol monomethyl ether in a low acid apple juice containing
no declared vitamin C were compared with those in the same juice containing added vitamin C (60 mg/175 ml); there were no
apparent losses at room temperature over 20 days or at 80°C after 20 min. in either juice. Altertoxin I was moderately stable
in pH 3 buffer (75% remaining after a two week period). Furthermore, altertoxin I was stable or moderately stable in three
brands of apple juice tested over 1–27 day periods and in a sample of red grape juice over 7 days. It is concluded that altertoxin
I is sufficiently stable to be found in fruit juices and should be included in methods for alternariol and alternariol monomethyl
ether. 相似文献
73.
Kristin Helle Michael Pennington Bjarte Bogstad Geir Ottersen 《Environmental Biology of Fishes》2002,65(3):341-348
A high growth rate for Arcto-Norwegian cod, Gadus morhua, in the Barents Sea and adjacent areas from the larva period to the 0-group enhances survival and ultimately recruitment to the fishery. However, it appeared that high growth rates for a cohort through the 0-group were not continued as the cohort ages. Based on survey data, there was a significant negative correlation between the average length at the 0-group and its average length at ages 2 through 8. We provided evidence suggesting that this phenomenon was caused by the inter-annual variability in inflow of warm, prey-rich Atlantic water into the Barents Sea from the Norwegian Sea. Enhanced inflow provided favorable conditions for cod growth during the larva and juvenile pelagic intervals. However, this same strong inflow carried a proportion of the cohort farther to the east in the Barents Sea, where the bottom water is colder than in the west. The colder conditions experienced by such cohorts, as compared to cohorts that have a more westerly settlement, led to slower growth prior to age 2. Slow growth during this interval appeared to be the reason for these cohorts' relatively smaller mean length at older ages. 相似文献
74.
75.
K J Purdie J Pennington C M Proby S Khalaf E M de Villiers I M Leigh A Storey 《The EMBO journal》1999,18(19):5359-5369
An aetiological role has been proposed for human papillomavirus (HPV) in skin carcinogenesis within the immunosuppressed patient population. To examine this possibility, we have focused on an HPV type that, to date, has been identified only in the cutaneous lesions of renal transplant recipients despite a high degree of sequence homology with other HPVs commonly found in warts in the general population. We report that the non-coding region of this virus, HPV type 77, contains a consensus binding site for the tumour suppressor protein p53, and we show by gel-retardation analysis that this sequence does indeed bind p53. Furthermore, using reporter gene assays, we demonstrate that HPV77 promoter activity is stimulated by UV radiation and that this response is mediated through the p53 binding site. This is the first report of a p53-dependent positive response element within a viral genome. Our results suggest a possible novel mechanism by which specific types of HPV might act as cofactors with UV radiation in cutaneous transformation. 相似文献
76.
The vacuum flask method of using boiling water to decontaminate soft contact lenses is better and less expensive than other ways of using moist heat and can be safely and effectively applied under most domestic circumstances. 相似文献
77.
The pattern of polypeptides specifically secreted by cells after infection with vaccinia virus has been analyzed. A complex pattern of apparently virus-specified polypeptides exhibiting temporal control of the type seen with intracellular polypeptides after virus infection was observed. Some of the specifically secreted polypeptides were shown to be modified by glycosylation and sulfation. The possible significance of these results is discussed. 相似文献
78.
79.
80.
GTP gamma S inhibits early c-myc protein accumulation but not DNA synthesis in Swiss 3T3 fibroblasts
Quiescent Swiss 3T3 fibroblasts stimulated with epidermal growth factor and insulin showed large transient increases in c-myc mRNA and c-myc protein accumulation which were maximal at about 2 h after addition of the co-mitogens. When the cells were loaded with 0.1 mM of guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) by transient permeabilisation immediately before mitogenic stimulation, the increase in c-myc mRNA was similar to that observed in unloaded cells but the corresponding c-myc protein peak was reduced by at least 95%. The GTP gamma S completely blocked incorporation of [35S]methionine into cell proteins for 3-4 h after addition of the mitogens, but not thereafter, and caused a delay in the subsequent onset of DNA synthesis by the same period. The data show that less than 5% of the early increase in c-myc protein normally observed after mitogenic stimulation is required for its obligatory role in the progression of cells to S phase implied by other evidence. 相似文献