| 1. |
- Cui, Song, et al.
(författare)
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Heavy Metals in Sediment from the Urban and Rural Rivers in Harbin City, Northeast China
- 2019
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Ingår i: International Journal of Environmental Research and Public Health. - : MDPI. - 1661-7827 .- 1660-4601. ; 16:22
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Tidskriftsartikel (refereegranskat)abstract
- The concentrations and ecological risk of six widespread heavy metals (Cu, Cr, Ni, Zn, Cd and Pb) were investigated and evaluated in sediments from both urban and rural rivers in a northeast city of China. The decreasing trend of the average concentration of heavy metals was Zn > Cr > Cu > Pb > Ni > Cd in Majiagou River (urban) and was Zn > Cr > Pb > Cu > Ni > Cd in Yunliang River (rural). The results showed that the concentrations of Cd and Zn were significantly elevated compared to the environmental background value (p < 0.05). Half of all sampling locations were deemed 'contaminated' as defined by the improved Nemerow pollution index (P-N' > 1.0). Applying the potential ecological risk index (RI) indicated a 'high ecological risk' for both rivers, with Cd accounting for more than 80% in both cases. Source apportionment indicated a significant correlation between Cd and Zn in sediments (R = 0.997, p < 0.01) in Yunliang River, suggesting that agricultural activities could be the major sources. Conversely, industrial production, coal burning, natural sources and traffic emissions are likely to be the main pollution sources for heavy metals in Majiagou River. This study has improved our understanding of how human activities, industrial production, and agricultural production influence heavy metal pollution in urban and rural rivers, and it provides a further weight of evidence for the linkages between different pollutants and resulting levels of heavy metals in riverine sediments.
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| 2. |
- Li, Jing, et al.
(författare)
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Teaching algebraic equations with variation in Chinese classroom
- 2011
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Ingår i: Early Algebraization. - Berlin, Heidelberg : Springer. - 9783642177347 ; , s. 529-556
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Bokkapitel (refereegranskat)abstract
- This chapter gives a detailed analysis of how teaching with variation is helpful for students’ learning of algebraic equations by using typical teaching episodes in grade seven in China. Also, it provides a demonstration showing how variation is used as an effective way of teaching through the discussion after the analysis.
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| 3. |
- Liu, Zhikun, et al.
(författare)
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A review of spatiotemporal patterns of neonicotinoid insecticides in water, sediment, and soil across China
- 2022
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Ingår i: Environmental Science and Pollution Research. - : Springer. - 0944-1344 .- 1614-7499. ; 29:37, s. 55336-55347
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Forskningsöversikt (refereegranskat)abstract
- Neonicotinoid insecticides (NNIs) have been widely used to control insect pests, while their environmental residues and associated hazardous impacts on human and ecosystem health have attracted increasing attention worldwide. In this study, we examined the current levels and associated spatial and temporal patterns of NNIs in multiple environmental media across China. Concentrations of NNIs in surface water, sediment, and soil were in the range of 9.94-755 ng.L-1, 0.07-8.30 ng.g(-1) DW, and 0.009-356 ng.g(-1) DW, respectively. The high levels of NNIs in surface water, such as in Yangtze River (755 ng.L-1), North River (539 ng.L-1), Nandu River (519 ng.L-1), and Minjiang River (514 ng.L-1), were dominated by imidacloprid, thiamethoxam, and acetamiprid due to their extensive use. The levels of NNIs in sediments were relatively low, and the highest concentration (8.30 ng.g(-1) DW) was observed in Dongguan ditch. Sediment-water exchange calculated from fugacity fraction indicated that NNIs in sediment can be released back into the water due to their high solubility and low KOW. Soils from agricultural zones contained the largest residual NNIs, with imidacloprid concentrations in cultivated soil reaching 119 ng.g(-1) DW. The calculated leaching potential showed that clothianidin has the highest migration potential to deep soil or groundwater. The monitored data of NNIs presented a decreasing trend from 2016 to 2018, which might be caused by the implementation of relevant control policies for NNI applications. The high levels of NNIs mainly occurred in southern China due to frequent agricultural activities and warm and humid meteorological conditions. The results from this study improve our understanding of the pollution levels and environmental behavior of NNIs in different environmental media across China and provide new knowledge that is needed for making future control policies for NNIs production and application.
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| 4. |
- Peng, Aihui, et al.
(författare)
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Swedish and Chinese teachers' views on what constitutes a good mathematical test task : A pilot study
- 2015
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Ingår i: Proceedings of CERME 9. - : European Society for Research in Mathematics Education. ; , s. 1738-1744
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Konferensbidrag (refereegranskat)abstract
- Mathematical tasks in tests are central to students’ learning.Research shows that there is a significant gap between mathematical tasks in national tests and teacher-made tests.In this pilot study we examineeighteenSwedish and Chinese teachers’ viewsonwhat constitutes of a good mathematicaltesttaskat thelowersecondary school level. E-Mail Interviewing is conducted by presenting sevenmathematical tasks from national tests inSweden and China, respectively. The preliminary results show that Swedish and Chinese teachers hold some common viewsonthecharacteristics of good mathematical test tasks, but they also show different viewson the cognitively demanding tasks. Implications of the results and the methodology informed by the pilot study are discussed.
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| 5. |
- Snyder, Gretchen L., et al.
(författare)
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Preclinical profile of ITI-214, an inhibitor of phosphodiesterase 1, for enhancement of memory performance in rats
- 2016
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Ingår i: Psychopharmacology. - : Springer Science and Business Media LLC. - 0033-3158 .- 1432-2072. ; 233:17, s. 3113-3124
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Tidskriftsartikel (refereegranskat)abstract
- Rationale: Therapeutic agents for memory enhancement in psychiatric disorders, such as schizophrenia, are urgently needed.Objective: The aim of this study is to characterize the preclinical profile of ITI-214, a potent inhibitor of phosphodiesterase 1 (PDE1).Methods: ITI-214 was assayed for inhibition of PDE1 versus other PDE enzyme families using recombinant human PDE enzymes and for off-target binding to 70 substrates (General SEP II diversity panel; Caliper Life Sciences). Effects of ITI-214 (0.1–10 mg/kg, po) on memory performance were assayed in rats using the novel object recognition (NOR) paradigm, with drug given at specified time points prior to or following exposure to objects in an open field. ITI-214 was evaluated for potential drug-drug interaction with risperidone in rats using conditioned avoidance response (CAR) and pharmacokinetic assessments.Results: ITI-214 inhibited PDE1A (Ki = 33 pmol) with >1000-fold selectivity for the nearest other PDE family (PDE4D) and displayed minimal off-target binding interactions in a 70-substrate selectivity profile. By using specific timing of oral ITI-214 administration, it was demonstrated in the NOR that ITI-214 is able to enhance acquisition, consolidation, and retrieval memory processes. All memory effects were in the absence of effects on exploratory behavior. ITI-214 did not disrupt the risperidone pharmacokinetic profile or effects in CAR.Conclusions: ITI-214 improved the memory processes of acquisition, consolidation, and retrieval across a broad dose range (0.1–10 mg/kg, po) without disrupting the antipsychotic-like activity of a clinical antipsychotic medication, specifically risperidone. Clinical development of ITI-214 is currently in progress.
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| 6. |
- Zhang, Fuxiang, et al.
(författare)
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Heavy metals exposure risk to Eurasian Spoonbill (Platalea leucorodia) in wetland ecosystem, Northeast China
- 2020
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Ingår i: Ecological Engineering. - : Elsevier. - 0925-8574 .- 1872-6992. ; 157
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Tidskriftsartikel (refereegranskat)abstract
- Qixing River wetland is very representative of the marsh environment of Sanjiang Plain, northeast China. The wetland plays an important role in maintaining ecological service functions especially for protecting migratory birds. Despite Qixing River wetland being impacted by a number of diffuse and point sources of pollution (primarily from agricultural activities), a comprehensive survey of heavy metal exposure risk to migratory birds has never been undertaken. Identifying heavy metals exposure risk is significant for further improving the protection scheme of migratory birds. In the present study, the comprehensive water pollution index (WPI) and geo-accumulation index (I-geo) were calculated to assess the degree of contamination of water and sediments, respectively. Single-pollutant exposure metrics (HQ) were applied to measured concentrations in order to estimate the heavy metal exposure risk to migratory birds. In addition, an integrated hazard index (HI) was derived to assess the comprehensive risk of exposure to multiple heavy metals and associated risk threshold values calculated. The decreasing trends of average concentration of heavy metals were Zn > Cr > Ni > Cu > Pb > Cd in sediments and Zn > Cr > Pb > Ni > Cu > Cd in water. Concentrations of Cr were significantly elevated compared to the threshold of Aquatic Life Water Permissible Limits (AWPL) and Sediment Quality Guidelines (SGQ) (p < 0.01), thus may pose negative impacts to the aquatic ecological system. Values of WPI indicated 'Clean' status for more than 85% sampling sites with Zn accounting for 58% of the value of the WPI. Most of the sediment sampling locations were deemed to be 'Clean' or 'Low' status as defined by I-geo with Zn and Cd (mainly derived from agricultural sources) identified as the dominant indicators of pollution. Comprehensive exposure risk assessment indicated 'Moderate' risk (HI > 1) status for local populations of Eurasian Spoonbill. Despite the majority of heavy metals (except for Zn) being assigned 'Clean' or 'Low' pollution status, the elevated hazard quotient (HQ > 3) associated with Cr enhanced overall values of HI, especially for nestlings, indicating that current pollution control measures are insufficient for the protection of migratory birds. This study has supplemented current knowledge of the impacts of agriculture on wetland ecosystems and provides evidence that exposures of migratory birds to some heavy metals may exceed 'safe' levels. This study thus provides a scientific rationale for determining the safe feeding water depth for migratory birds.
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| 7. |
- Zhang, Fuxiang, et al.
(författare)
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Levels, Inventory, and Risk Assessment of Heavy Metals in Wetland Ecosystem, Northeast China : Implications for Snow Cover Monitoring
- 2021
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Ingår i: Water. - : MDPI. - 2073-4441. ; 13:16
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Tidskriftsartikel (refereegranskat)abstract
- Snow cover is a unique environmental medium in cold regions that can cause potential risks to the ecological environment, due to the release of pollutants that are stored in it. In this study, the Qixing River wetland, located in the Sanjiang Plain of China, was taken as the target research area. Heavy metals in snow cover, including Cu, Ni, Cr, Cd, Pb, and Zn were measured at 19 sampling sites. The results showed that the average concentrations of heavy metals were: Zn (103.46 +/- 39.16) > Pb (13.08 +/- 4.99) > Cr (11.97 +/- 2.82) > Ni (9.55 +/- 4.96) > Cu (6.19 +/- 1.79) > Cd (0.55 +/- 0.25) mu g center dot L-1. Cr and Zn were between Class I and Class II in the "Environmental Quality Standards for Surface Water" of China (GB3838-2002). Pb in snow exceeded the upper limit of Class II, and was significantly higher than concentrations measured in water samples from the Qixing River wetland (p < 0.05), indicating that atmospheric deposition during winter was the major source of Pb. The water pollution index (WPI) indicated that 61.0% of samples could be considered of "clean" status, while the contribution of Zn, Pb, and Cr to WPI were 33.3%, 21.0%, and 19.3%, respectively. A preliminary evaluation of heavy metal inventory in snow cover showed that the residue level of Zn was the highest (2313.57 +/- 1194.67 mu g center dot m(-2)), while Cd was the lowest (13.91 +/- 10.45 mu g center dot m(-2)). The areas with high residues of heavy metals were all located near the buffer zone of the wetland (except for Zn), where snow depth tended to be greatest. Exposure analysis indicated that the risks to winter resident birds from snow ingestion was minimal, but it should be noted that the exposure risk was higher in birds with lower bodyweights. This study provides important information and scientific knowledge on the pollution characteristics and residue inventory of heavy metals in wetland ecosystems, while the results can also provide a monitoring method, reflecting atmospheric environmental quality at a local or regional scale.
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