AbstractThe aim of the research was to evaluate the effect of consumption of selenium-enriched pork on selected health indicators of probands. The intake of feed mixture with increased organic selenium at the dose of 0.3?mg.kg?1 probably increases selenium concentration in MSM (musculus semimembranosus). In the pork enriched with organic selenium, the concentration was higher by 1.045?±?0.10?mg.kg?1 compared with the control group 0.701?±?0.05?mg.kg?1 at significance P?<?0.001. Sixteen participants in the experiment were represented by 8 men at the average age of 41.5?±?11.9?years and 8 women at the average age of 41.4?±?7.9?years. All the probands consumed meat enriched with selenium three times a week during one month. By consumption of the enriched pork, there was an increase of the selenium concentration in blood serum of probands traced with selenium increase from 73.19?±?15.68?μg.L?1 to 73.73?±?15.13?μg.L?1 (P?>?0.05). From the results we can see that consumption of enriched pork with selenium was significantly manifested in lowering of total cholesterol levels, which was associated with LDL cholesterol lowering (P?<?0.05). Differences among the HDL cholesterol and triglycerides samples were not significant. 相似文献
Uptake of 233Pa from sea water by mussels Mytilus galloprovincialis L. and shore crabs Carcinus mediterraneus
Csrn. was studied. Results indicate a high contamination factor in digestive tract, gills and skeleton of both investigated species and an increment of the contamination factor in mussel byssus. In spite of this, reproductive system, muscle and hemolymph were only negligibly contaminated. The presence of complexone EDTA in sea water has no effect on uptake of 233Pa in the animal tissues tested. 相似文献
The effects of temperature and body size on the intermolt periods (molting frequencies) of the North Pacific euphausíid Euphausia pacifica and the Mediterranean forms of Meganyctiphanes norvegica, Euphausia krohnii, Nematoscelis megalops, and Nyctiphanes couchii were studied under controlled conditions in the laboratory. Mean intermolt periods for E. pacifica and M. norvegica were inversely and linearly related to temperature, over temperature ranges which the euphausiids normally encounter in the sea. At higher temperatures there was a tendency for three size groups of M. norvegica to approach a minimum intermolt period independent of temperature. M. norvegica cycled for different time periods between 13° and 18°C molted regularly at mean frequencies which would be expected if the animals had been held constantly at the timeweighted means of the two experimental temperatures. The increase in mean intermolt period per unit weight was faster in small, fast-growing M. norvegica than in large, slow-growing adults. This relationship was corroborated by following the changes in the intermolt period of an actively growing individual N. couchii over an 11 month period. Neither feeding nor the time of year of collection affected the molting frequency as long as temperature and animal weight were held constant. No tendency was found for euphausiids of the same species and/or size, and from the same collection, to molt on the same night. Molting occurred at night 80 to 90% of the time for all species, over the temperature ranges normally experienced by the euphausiids in the sea, and over all animal weights tested. There appeared to be a weakening of the night-time molting rhythm at low temperatures. Although neither temperature nor anímal weight substantially affected the night-time molting rhythm, both affected the mean intermolt period. Therefore, both temperature and body size apparently act together to adjust the length of the intermolt period of each individual in increments of whole days, but they exert little control over time of molting within any 24h period. No information was obtained regarding the factors which specify night-time molting over daytime molting within any 24 h period; however, regulation of certain hormone activities is probably involved. 相似文献
The dynamics of accumulation and loss of different physico-chemical forms of 106Ru were measured in the euphausiid Meganyctiphanes norvegica. The accumulation of 106Ru was directly related to the concentration of the radioisotope in solution, as evidenced by similar concentration factors for euphausiids in the low and high activity 106Ru chloride solutions. The chemical form of the radioisotope in solution had a pronounced effect on the uptake, with 106Ru chloride fractions being accumulated at a faster rate than 106Ru nitrosyl-nitrato complexes. Euphausiids lost 106Ru, previously accumulated from the 106Ru chloride complexes, at a faster rate than 106Ru which had been accumulated from 106Ru nitrosyl-nitrato forms. Also, in the case of the 106Ru chloride complexes, the loss rate was inversely proportional to the time allowed for isotope accumulation. The process of molting greatly accelerated the loss of 106Ru from euphausiids, with first molts shed during the loss phase accounting for 70 to 80% of the total 106Ru body burden. When euphausiids accumulated 106Ru from the food chain, the initial-loss rate was rapid due to large amounts of the radioisotope associated with fecal pellets; however, no relationship was found between loss rate and the number of food rations received. Molts from these individuals did not contain 106Ru, thus, loss from euphausiids obtaining this radioisotope through the food chain is mainly due to fecal pellet deposition and other excretion or exchange processes. 相似文献
Gamma-ray spectra of terra rossa soil and natural-phosphate ore have been measured in order to determine Th, U, K and 137Cs contents. It has been found that the phosphate ore contains an order of magnitude lower potassium content than average (n.10?3g/g), an average content of thorium (n.10?6g/g), and a two orders of magnitude higher concentration of uranium (n.10?4g/g) than the averages found in the Earth's crust. Terra rossa contains two to three times higher concentrations of Th and U, average concentrations of K, and up to 0.2 Bq/g of 137Cs. Both materials, in our opinion, are suitable for large-sample-calibration purposes and are applicable for radioecological studies of soils. 相似文献
This study presents a comprehensive characterization of occurrence and levels of 16 polycyclic aromatic hydrocarbons (PAHs) in arable soils used for conventional and organic production in northern and central part of Serbia as well as cross-border region with Hungary. Furthermore, this study includes a characterization of PAH sources and carcinogenic/non-carcinogenic human health risk for PAHs accumulated in analysed arable soils. The total concentration of 16 PAHs varied between 55 and 4584 µg kg?1 in agricultural soil used for conventional production and between 90 and 523 µg kg?1 in agricultural soil used for organic production. High molecular weight (HMW) PAHs were dominant compounds with similar contribution in both soil types (86% and 80% in conventional and in organic soil, respectively). Principal component analysis and diagnostic ratios of selected PAHs were used for identification of PAH sources in the analysed soils. Additionally, positive matrix factorization was applied for quantitative assessment. The results indicated that the major sources of PAHs were vehicle emissions, biomass and wood combustion, accounting for?~?93% of PAHs. Exposure of farmers assessed through carcinogenic (TCR) and non-carcinogenic (THQ) risk did not exceed the acceptable threshold (TCR?<?10–6 and THQ?<?1). Oral ingestion was the main exposure route which accounted for 57% of TCR and 80% of THQ. It was followed by dermal contact. This investigation gives a valuable data insight into the PAHs presence in arable soils and reveals the absence of environmental and health risk. It also acknowledges the importance of comprehensive monitoring of these persistent pollutants.
We demonstrate the antioxidant potential of humic acids in (green) polymer chemistry. Lignite humic acids and its sodium and
ammonium salts were mixed at different concentrations with polyvinyl alcohol and thermogravimetry was used to assess the influence
on the thermo-oxidative stability of resulted blends. Both protonized form and ammonium salt of humic acids caused increased
stability of investigated polymers in the studied concentration range (0.5–10% of humic acids in polymer). In contrast to
protonized form, the ammonium salt also showed moderating effect on polymer degradation kinetics. Sodium salts caused substantially
lower stabilizing effect and presence of 10% of humic matter caused even destabilization. In all cases, however, when the
degradation has already started, the presence of humic acids and its salts caused more intensive polymer decomposition, which
resulted in lower weight of char. 相似文献
The work studies the photocatalytic activity and the antifungal efficiency of the TiO2/Zn-Al coatings placed on the target commercial façade paints. The photocatalytic active nanocomposite based on TiO2 and Zn-Al-layered double hydroxides (ZnAl-LDHs) was synthesized by a wet impregnation technique with 3 % w/w TiO2. The freshly prepared suspension was applied by spray technique on the surfaces of the white façade paints. The goal of the work was to develop a method that quickly quantifies the antifungal activity of the commercial façade paints with and without biocidal components covered with a photocatalytic coating. The essence of the proposed method is the monitoring of the fungal growth (artificial ageing conditions) and the quantification of its development (UV-A 0.13 mWcm?2) on the façade paint surfaces. A special fungus nutrient (potato dextrose agar (PDA)) was inoculated with the spores of the Aspergillus nigerATCC 6275, and the test samples (façade paints with and without photocatalytic coating) were placed on the inoculated nutrient in the petri dishes. The images of the fungal growth on the samples of the facade paints, during a period of 5 days, were imported into Matlab R2012a where they were converted to binary images (BW), based on the adequate threshold. The percentage of the surface coverage was calculated by applying the specifically written program code which determines the ratio of the black and white pixels. The black pixels correspond to the surface covered with hyphae and mycelia of the fungus. 相似文献
In the pioneer days, the main driving forces for research of organics in drinking water treatment (DWT) were human health risks and optimisation of technology. The focus was on natural organic matter (NOM) structure, disinfection by-products (DBPs) formation, NOM removal by means of coagulation, adsorption, and oxidation, and development of the most efficient water treatment trains. Surprisingly, after decades of research, rapid development of analytical techniques and progress in risk assessment, the same driving forces are still in the limelight — although the topics have changed slightly. The attention switched from trihalomethanes to a new generation of DBPs. The definition of hydrophilic/hydrophobic NOM depends on the technique used for characterisation. It has become evident that numerous organic compounds can threaten water supply sources. Some of them had been ignored or overlooked in the past, but have recently been detected by advanced analytical tools even in drinking water. Prioritisation becomes priority per se. As far as processes are concerned, mainstream research has been following three lines: fouling mechanisms, application of hybrid processes and interactions between synthetic organic chemicals, other water constituents and materials used in DWT. Significant development has been made in membrane technology. This paper presents a broad overview of the recent organics research. Although the state-of-the-art technologies seem to have an answer to each and every question raised, it is still necessary to deal with specific problems on a case-by-case basis mainly due to the unique nature of NOM and different xenobiotics that may appear in various types of waters. In the end, human health risk, which derives from the presence/absence of organics, is only the tip of the iceberg — underneath lies a whole new universe — the socio-economic aspect of water treatment and quality that deserves much more attention. 相似文献