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In this study, several novel blend membranes based on ligand-immobilized amphiphilic carbonaceous particles (ACPs) and matrix polymer polyvinylidene fluoride (PVDF) were prepared by an immersion phase inversion method. The effects of the ACP content on filtration performance of the membrane were investigated. Endotoxin removal with blend membranes at different pH values and ionic strengths was analyzed and discussed. The results indicated that the use of ACPs not only achieved uniform and stable incorporation of water-soluble ligands into the hydrophobic polymer membrane but also improved its filtration properties, including permeability, strength, hydrophilicity and antifouling ability. The blend membranes with the optimum particle content showed good performances in filtration and were highly effective in removing endotoxins from both buffer and protein solutions under properly chosen conditions. More than 99.8% of endotoxin removal and more than 90% of BSA recovery were achieved when 1 mg L−1 of BSA solution with 116 EU mL−1 of the endotoxin content was treated at pH 4.7. All the above suggested that the carrier-dispersed method described herein was one of the effective methods in constructing functionalized blend membrane absorbers. [ABSTRACT FROM AUTHOR]

High-resolution satellite images such as those from Ikonos and QuickBird are increasingly available and are considered a valuable tool for extracting the consequences of gully erosion, and QuickBird imagery has been used to map gully features. To evaluate the accuracy of extracting morphological parameters of bank gullies including area, perimeter, and length from QuickBird imagery by manual visual interpretation, and to analyze the causes of errors, 20 bank gullies were selected in Hegou catchment and Qiaogou catchment located in the Loess Plateau of northern Shaanxi province, respectively. 3D laser scanner was used to measure the topography of bank gullies within two weeks after the QuickBird images were taken. The interval among measurement points of 3D laser scanner was set as 0.15 m. 3D laser scanner had been increasingly used to measure the topography as it can provide a high accuracy, non-contacted, penetrating and rapid method that enables the rapid production of accurate, high-resolution digital elevation model (DEM). Based on Delaunay triangulated irregular networks (TIN), then DEM with the pixel size of 0.15 m × 0.15 m was created using the 3D Analyst extension of ArcGIS 9.3. On this basis, the values of morphological parameters extracted from DEM were taken as actual values and errors of morphological parameters of bank gullies extracted from QuickBird imagery were determined. The average absolute error, maximum absolute error, average relative error, maximum relative error, and maximum relative error among different interpretation persons were used to assess the accuracy of manual visual interpretation of QuickBird imagery. The results showed that maximum relative error of area and perimeter ranged from 4.1% to 22.2% and 1.4% to 22.2% in Hegou catchment, respectively, while maximum relative error ranged from 2.4% to 22.6% for area and 4.5% to 29.7% for perimeter in Qiaogou catchment, respectively. Although maximum relative error appeared to be large for some gullies, average relative error of area and perimeter were both about 5% in two study areas. In addition, by overlaying the two valley regions extracted from QuickBird imagery and DEM, the area that the distance offsets was larger than 0.6 m (QuickBird image one pixel value) remained below 4%. Average relative error of gully length in Hegou catchment and Qiaogou catchment were about 2% and 5%, respectively, with corresponding average of the average absolute error of 0.5 m and 0.75 m. Correlation analysis showed that average relative error, maximum relative error and maximum relative error among different interpretation persons were negatively correlated with the area and length of bank gully (P<0.05), which meant that the larger the area and length of bank gully were, the smaller the errors were. This suggested that choosing large gullies would reduce the errors when the morphological parameters were extracted manually from QuickBird imagery. The accuracy of manual visual interpretation was also influenced by the vegetation types near the gully boundary. Catchments which land was covered with native grassland had higher precision than those were covered with shrub and grass. Overall, QuickBird imagery can provide reliable data source for extracting morphological parameters of bank gullies. The results can provide the references for assessing gully erosion using QuickBird imagery at larger spatial scales rather than direct field measurements. [ABSTRACT FROM AUTHOR]

Three soil property test data of microtopography in the semi-arid Loess Plateau were used to compare the following three soil quality evaluation methods: correlation coefficient method, factor analysis method and Nemoro index method. The results of these methods were analyzed and compared to determine the most suitable method for comprehensive evaluation of soil quality. While correlation coefficient method and factor analysis method produced similar results, Nemoro index method showed several differences from the othertwo methods and exhibited higher sensitivity in its assessment results. The soil quality index (SQI) parameters of three methods showed consistent scales and variation trends among the various microtopographies, and there was a highly significant linear positive correlation between the SQI parameters of any two given methods. This result suggested that the three methods were all reliable and could be employed for comprehensive assessment of soil quality of microtopography in the study region. However, the Nemoro index method involves relatively uncomplicated mathematics and is very easy to absorb, and thus should be preferentially employed when three grading standards can be identified. The factor analysis method is the next most preferable, followed by correlation coefficient method.

Soil moisture is the primary factor limiting plant growth and vegetation rehabilitation in the loess region of northern Shaanxi, China. This 5-year (2008-2012) study investigated methods of selecting appropriate microsites for vegetation restoration based on efficient use of soil moisture; 5-year data were compared with 56 years of precipitation data using standardized precipitation index. In addition, the effects of microtopography on the spatiotemporal variations of soil moisture were analyzed at the Wuqi Ecological Station of Beijing Forestry University. Results showed that average annual precipitation during last 5 years fell by 12.4% during the growing season compared with 1957-2012 data and soil moisture content at depth of 0-160 cm under went dramatic changes and became relatively low in July and August. Soil moisture content varied in different microtopographical units as follows: gullies > gently-sloped terraces > collapsed soils > undisturbed slopes (control) > furrows > escarpments. The vertical distribution of soil moisture content in different microtopographical units showed dramatic changes at depth of 0-40 cm. Soil moisture content of gently-sloped terraces, gullies, collapsed areas, furrows, and undisturbed slopes was highest at depth of 80-160 cm with a level of instability at depth of 40-80 cm. For gently-sloped terraces and gullies, soil moisture content followed the order of 40-80 cm > 0-40 cm; for collapsed areas, furrows, and undisturbed slopes, soil moisture content follows the order of 0-40 cm > 40-80 cm. For escarpments, soil moisture content varied with depth in a different pattern: 0-40 cm > 80-160 cm > 40-80 cm. This study is of theoretical significance and will help guide the sustainable development of ecological restoration and vegetation rehabilitation in the Loess region.