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61.
Bengt Steen 《The International Journal of Life Cycle Assessment》2007,12(2):103-108
Goal, Scope and Background The life cycles of many products including textiles contain chemicals for which process flow data are not known or are too
time consuming to collect. Although each chemical may not contribute significantly to the LCA results of the product, which
might justify excluding them, but together their contribution could be significant. Similarly, rough estimates of the process
flows for the production of a single chemical may be very uncertain and considered meaningless, while the estimates of the
cumulative data of process flows for several chemicals may be less uncertain and be a meaningful contribution to the quality
of the LCA results. There are methods for estimation of process flows for different types of products, with varying demands
regarding input data and time and with varying accuracy of the results. This work contributes to the available methods, focusing
on simple estimations for production of chemical substances. The goal was to create a fast method for estimation of emissions,
resource and energy flows (process flows) for the production of chemicals, based on easily available data on the properties
of the chemicals. The process flows investigated were limited to those normally associated with process industries and contributing
most to depletion of resources, to global warming, acidification, eutrophication and photochemical ozone production, i.e.
use of energy, crude oil, coal, natural gas, uranium in ore and emissions of CO2, SOx, NOx, NMVOC, methane, BOD, COD and total
N. Toxic substances were excluded, since toxic emissions are substance specific and cannot be included in a generalization.
Method Available data for the process flows for the production of chemicals of mainly fossil origin were correlated to properties
of chemicals such as amount of carbon in the molecule, heat of formation and average number of chemical reaction steps in
the production. The production procedures were found in readily available literature. Up to about six reaction steps were
evaluated in the correlation study. The variations in the process flows among the chemicals studied were calculated.
Results and Discussion There were weak correlations between average number of chemical reaction steps in the production and energy use, COD measured
in water emissions, and SOx and NOx emissions to air. For the remaining properties of chemicals and process flows, there were
only weak correlations for share of double bonding in the molecule if only molecules containing double bondings were included.
Conclusions The precision in estimation of the process flows increases non-significantly when adding information on the number of reaction
steps or share of double bonding for chemicals containing double bonding is added.
Recommendations and Outlook It seems reasonable to start with a simple grouping method to estimate the process flows for the production of a chemical
of fossil origin. Further investigations might investigate whether there is a correlation between process flows and the costs
of chemicals, and further study the correlations between process flows and share of double bonding for chemicals containing
double bondings. 相似文献
62.
There are four species of Gymnetron in China recorded to date including Gymnetron
miyoshii Miyoshi, 1922, Gymnetron
villosipenne Roelofs, 1875, Gymnetron
auliense Reitter, 1907 and Gymnetron
vittipenne Marseul, 1876, of which the last two are new country records. The pre-imaginal stages including eggs, mature larvae and pupae of Gymnetron
miyoshii, Gymnetron
auliense and Gymnetron
vittipenne are described and illustrated. In addition, their diagnostic characters (larvae and pupae) are discussed and differentiated, and notes on some of their biological parameters are provided. Potential ecological impacts between Gymnetron weevils and their host Veronica spp. also are provided. 相似文献
63.
Yamazaki Y Kido Y Hidaka K Yasui H Kiso Y Yakushiji F Hayashi Y 《Bioorganic & medicinal chemistry》2011,19(1):595-602
A new bioactive photoaffinity probe KPU-252-B1 (4) possessing a biotin tag on the oxazole ring of a potent plinabulin derivative KPU-244 (2) was synthesized via the CuI-catalyzed Huisgen’s cycloaddition reaction to understand the precise binding mode of the diketopiperazine-based anti-microtubule agent plinabulin on tubulin. Probe 4 showed significant binding affinity toward tubulin and cytotoxicity against an HT-29 cells. A photoaffinity labeling study suggested that probe 4 specifically recognizes tubulin at a binding site that binds plinabulin or colchicine, most likely near or at the colchicine binding site, which is located at the interfacial region formed by ??-and ??-tubulin association. The results also demonstrated that probe 4 may serve as a useful plinabulin chemical probe to investigate the molecular mechanism by which anti-microtubule diketopiperazine derivatives operate. 相似文献
64.
Cole LM Djidja MC Bluff J Claude E Carolan VA Paley M Tozer GM Clench MR 《Methods (San Diego, Calif.)》2011,54(4):442-453
Characterising the protein signatures in tumours following vascular-targeted therapy will help determine both treatment response and resistance mechanisms. Here, mass spectrometry imaging and MS/MS with and without ion mobility separation have been used for this purpose in a mouse fibrosarcoma model following treatment with the tubulin-binding tumour vascular disrupting agent, combretastatin A-4-phosphate (CA-4-P). Characterisation of peptides after in situ tissue tryptic digestion was carried out using Matrix-Assisted Laser Desorption/Ionisation-Mass Spectrometry (MALDI-MS) and Matrix-Assisted Laser Desorption/Ionisation-Ion Mobility Separation-Mass Spectrometry Imaging (MALDI IMS-MSI) to observe the spatial distribution of peptides. Matrix-Assisted Laser Desorption/Ionisation-Ion Mobility Separation-Tandem Mass Spectrometry (MALDI-IMS-MS/MS) of peaks was performed to elucidate any pharmacological responses and potential biomarkers. By taking tumour samples at a number of time points after treatment gross changes in the tissue were indicated by changes in the signal levels of certain peptides. These were identified as arising from haemoglobin and indicated the disruption of the tumour vasculature. It was hoped that the use of PCA-DA would reveal more subtle changes taking place in the tumour samples however these are masked by the dominance of the changes in the haemoglobin signals. 相似文献
65.
Lister AL Van Der Kraak GJ Rutherford R MacLatchy D 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2011,154(4):278-287
Fundulus heteroclitus, the mummichog or Atlantic killifish, is the dominant small-bodied fish species of the east coast estuaries and salt marshes of Canada and the USA, where it is present as two subspecies, the northern F. h. macrolepidotus and the southern F. h. heteroclitus. Recently identified as the premier teleost model in environmental biology, the species has long been of value in understanding evolved tolerance to toxicants and more lately in adding to our knowledge about reproductive effects of environmental endocrine disruptors. The body of literature on F. heteroclitus ovarian physiology and reproduction, from both field and laboratory studies, provides the foundation for present work focused on understanding the reproductive effects and modes of action of environmental toxicants. In this paper, we review the environmental and endocrine factors controlling ovarian and reproductive cycling in F. heteroclitus, noting specifics related to field and laboratory studies on the two subspecies as well as key research gaps compared to other fish species. We also summarize recent development of methodologies to study the effects of environmental contaminants on endocrine signalling and egg production in F. heteroclitus. Continued efforts to progress both our fundamental understanding of reproductive physiology in mummichog, coupled with studies focused on the modes of action of environmental contaminants, have high potential to further develop this teleost model. While the model may presently lag behind those based on other species of fish, the unique biochemical and physiological adaptations which allow F. heteroclitus to adapt to changing environmental and toxic conditions provide a valuable experimental system for comparative physiologists, ecotoxicologists and evolutionary biologists. 相似文献
66.
Hydroxylated polychlorinated biphenyls are the metabolites produced from parent compounds by the drug-metabolizing enzyme cytochrome P450. These compounds are suspected to disrupt postembryonic neural development in the brains of mammals including humans. We studied the effects of these compounds on thyroid hormone function in the brain by using metamorphosing tadpoles of the African clawed toad (Xenopus laevis) as a model for mammalian postembryonic development. The metamorphosis assay revealed that these compounds inhibit thyroid hormone-induced metamorphosis. Genome-wide gene expression analysis in the brain following short-term exposure demonstrated that delayed metamorphosis could partially be caused by disruption of thyroid hormone-induced gene expression. Furthermore, we associated the terms of functional ontology with the genes, whose expression was disrupted by these compounds. We suggest that the use of a genome-wide analysis coupled with bioinformatics might provide an overview of the molecular mechanism underlying thyroid-disrupting activities in vivo. 相似文献
67.
68.
69.
Behavioral endocrinologists are aware that many hormones exhibit a diurnal rhythm, and attempt to correct for this pattern by collecting physiological samples only during specified time windows of varying lengths. In studies utilizing urinary measures of hormone levels, this window often spans 2 h or longer. In this study, we compared chimpanzee urinary cortisol levels in sample pairs collected within 1 h of each other in an attempt to validate the use of a time window for sample collection. Chimpanzees were housed at the University of Louisiana New Iberia Research Center and trained to urinate into a paper cup on command; a total of 41 sample pairs were included in this analysis. We found that mean cortisol levels in the two sets of samples, collected within 1 h or less of each other, were significantly different; the mean cortisol level of the first set of samples was significantly higher than that of the second set. This hormone's diurnal pattern of secretion accounts for this significant decrease over a very short time period. We conclude that collection methodologies involving time windows of 1 h or longer need to take into account such rapid changes in levels of excreted hormone. We advocate the use of methodological and statistical corrections to decrease the impact of short-term fluctuations in urinary cortisol. 相似文献
70.
A model for environmental sex reversal in fish 总被引:3,自引:0,他引:3
A mathematical model is presented which combines genetic XX-female/XY-male sex determination with environmental pressure for phenotypic sex reversal. This may occur when fishes are exposed to endocrine disrupters, specifically masculinization by exposure to androgens and feminization by exposure to estrogens. A generic model is derived for the sex ratio in successive generations and three special cases, with chronic and constant pressure to sex reverse, are discussed in detail. These show that, with extreme environmental pressure to masculinize, the male genotype is at risk of dying out but with less extreme pressure, masculinization will not be detectable since the proportion of phenotypic males becomes one-half. With feminization at any pressure to sex reverse, the male and female genotypes will be maintained in a stable sex ratio in which the proportion of genotypic males exceeds one-half and is close to one-half if YY offspring (eggs) are not viable. In converse, the model is also applicable to the genetic ZZ-male/ZW-female system of sex determination in fish. At present suitable data are not available with which to validate the model, but proposals are made for relevant experimental studies. 相似文献