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11.
Concentrations of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) in vacuum cleaner dust collected in Japanese homes 总被引:1,自引:0,他引:1
Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are shown to be globally distributed, environmentally persistent and bioaccumulative. Although there is evidence that these compounds exist in the serum of non-occupationally exposed humans, the pathways leading to the presence of PFOS and PFOA are not well characterized. The concentrations of PFOS and PFOA in the vacuum cleaner dust collected in Japanese homes were measured. The compounds were detected in all the dust samples and the ranges were 11-2500 ng g(-1) for PFOS and 69-3700 ng g(-1) for PFOA. It was ascertained that PFOS and PFOA were present in the dust in homes, and that the absorption of the dust could be one of the exposure pathways of the PFOS and PFOA to humans. With regard to risk management, it is important to consider the usage of PFOS and PFOA in the indoor environment in order to avoid further pollution. 相似文献
12.
Oxygen Permeability and Biodegradability of Polyuronic Acids Prepared from Polysaccharides by TEMPO-Mediated Oxidation 总被引:2,自引:0,他引:2
Yumiko?Kato Jun-ichi?Kaminaga Rukichi?Matsuo Akira?IsogaiEmail author 《Journal of Polymers and the Environment》2005,13(3):261-266
Polyuronic acids, i.e., amylouronic acid, cellouronic acid and chitouronic acid, were prepared from starch, cellulose and chitin, respectively, by the 2,2,6,6-tetramethylpiperidine-1-oxy radical (TEMPO)-mediated oxidation, and their gas-barrier properties and biodegradability were studied in consideration to use the polyuronic acids as flexible packaging films or coating materials. Cellouronic acid and amylouronic acid had excellent oxygen-barrier properties similar to that of poly(vinyl alcohol) (PVA), while chitouronic acid did not. The regular chemical structures of the former two polyuronic acids with no bulky substituents or adducts may have brought about such high oxygen-barrier levels. An oxidized product prepared form fine microcrystalline cellulose by the TEMPO-mediated oxidation was not completely dissolved in water, but became a paste. However, this paste also formed sufficiently smooth films by coating, and had good gas-barrier property. All polyuronic acids prepared were biodegradable; cellouronic acid and chitouronic acid had high degrees of biodegradability, while amylouronic acid had quite low value. These various characteristics are significant for end use of these new polyuronic acids as gas-barrier materials for biodegradable packaging. 相似文献
13.
Kikuchi T Miyazaki S Ohnishi H Takahashi J Nakajima Y Tsuji K 《Die Naturwissenschaften》2008,95(10):963-968
Evolution of caste is a central issue in the biology of social insects. Comparative studies on their morphology so far suggest
the following three patterns: (1) a positive correlation between queen–worker size dimorphism and the divergence in reproductive
ability between castes, (2) a negative correlation among workers between morphological diversity and reproductive ability,
and (3) a positive correlation between queen–worker body shape difference and the diversity in worker morphology. We conducted
morphological comparisons between castes in Pachycondyla luteipes, workers of which are monomorphic and lack their reproductive ability. Although the size distribution broadly overlapped,
mean head width, head length, and scape length were significantly different between queens and workers. Conversely, in eye
length, petiole width, and Weber’s length, the size differences were reversed. The allometries (head length/head width, scape
length/head width, and Weber’s length/head width) were also significantly different between queens and workers. Morphological
examinations showed that the body shape was different between queens and workers, and the head part of workers was disproportionately
larger than that of queens. This pattern of queen–worker dimorphism is novel in ants with monomorphic workers and a clear
exception to the last pattern. This study suggests that it is possible that the loss of individual-level selection, the lack
of reproductive ability, influences morphological modification in ants. 相似文献
14.
Online crowdfunding can help address the perennial financial shortfalls in environmental conservation and management. Although many online crowdfunding campaigns fail to collect any funds due to not achieving their targets, little is known about what drives success. To address this knowledge gap, we applied a mixed-methods approach to data from 473 successful and failed campaigns hosted on the online crowdfunding platform Readyfor. We found that fundraising performance varied by topic, with campaigns on pet animal management outperforming those focussed on landscape management and sustainable use. We also found that marketing strategies associated with online findability and increased reach through social networks, increased fundraising success. However, the existence of other environmental campaigns running simultaneously, reduced the chance of success, which implies that the selecting popular topics does not always increase the likelihood of success due to increased competition. Wider applications of marketing could enhance the ability of environmental crowdfunding campaigns to raise funds.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01522-0. 相似文献