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In this study, the potential regulatory effects of fulvic acid extracted from paper mill effluent (PFA) in apple replant disease (ARD) were investigated through a comprehensive experimental evaluation of the effects of PFA on soil properties, growth inhibition of apple replant pathogens, and growth of replanted Malus hupehensis Rehd. seedlings. PFA with a relatively lower molecular weight was mainly composed of carbohydrates, lignin derivatives, and polysaccharides and was rich in functional groups such as carboxyl and phenolic hydroxyl groups. Treatment with PFA dosages ranging from 2 to 3 g/pot significantly increased available phosphorus (P) in soil by 47.5 to 57.5% when compared with the control without PFA, indicating that PFA had a positive effect in activating P. In addition, PFA stimulated the growth of replanted seedlings by promoting root elongation, enhancing leaf photosynthesis, and increasing the activity of root antioxidant enzymes including superoxide dismutase, peroxidase, and catalase. However, no convincing evidence was found that application of different dosages of PFA had remarkable effects on soil pH, inorganic nitrogen, available potassium, organic matter, and the numbers of bacteria and fungi. Notably, PFA had no effect on the copy number of the main pathogenic fungi causing ARD, including Fusarium oxysporum, Fusarium solani, Fusarium proliferatum, and Fusarium moniliforme. Overall, PFA can alleviate ARD to a certain extent mainly through its effects on improving the resilience of replanted young seedlings rather than by affecting soil microorganisms or providing nutrients.

Exogenous application of nitrogen (N) and phosphate (P) has been demonstrated to alleviate apple replant disease (ARD). Yet, the effect of controlled-release diammonium phosphate (C-DAP), which continuously supply N and P for ARD control, is still poorly understood. Applying C-DAP markedly alleviated the typical symptoms of ARD. C-DAP maintained soil N and P at relatively high and stable levels during the entire growth period of the replanted seedlings, thus, limiting the copy number of the four key pathogenic

Plants promote the mineralization of soil organic phosphorus by secreting phosphatase into the rhizosphere, in addition they promote the growth of bacteria which also release phosphatase to the rhizosphere. Sugars are the main component of root exudates and a key driver of soil microbial activity. In this study, we added different concentrations of a range of sugars found in root exudates to the soil during maize growth to investigate whether sugars could stimulate alkaline phosphatase activity. Sugars increased alkaline phosphatase activity in soil, while different sugars increased this activity to different extents. Small concentration of sugars did not stimulate alkaline phosphatase activity in the rhizosphere, change the bacterial community structure or select phosphatase producing species such as Saccharimonadales. However, alkaline phosphatase activity was enhanced by larger concentration of added sugars, which increased indigenous soil Saccharimonadales abundance. Notwithstanding this, Saccharimonadales were rare in the microbial taxa at the order level and their relative abundance was only 2.1%–4.9% at different sugar concentration levels. Our results suggest that addition of sugars selected for indigenous soil Saccharimonadales, enhancing alkaline phosphatase activity in the rhizosphere. These rare microbial taxa may be a key species in soil phosphorus cycling.

To investigate the applicability of microbial induced calcite precipitation (MICP) to the solidification of municipal solid waste incineration (MSWI) fly ash, the following work are carried out. Firstly, three ureolytic strains, UR1, UR2 and UR3, were isolated and identified as Sphingobacterium cladoniae, Bacillus aryabhattai and Raoultella ornithinolytica, respectively. Secondly, the fly ash samples were solidified by the above three strains, and the case with strain UR2 displayed largest unconfined compressive strength of 0.740 MPa. Lastly, heavy metal leaching test was carried out for the solidified samples. The immobilization ratios for Cu, Pb, and Cd were in the range of 41–77%. The case with UR1 displayed higher immobilization ratios for Cu, Cr, and Cd, and UR2 exhibited higher immobilization ratio for Pb. Overall, strains UR1 and UR2 provide promising use for the solidification of MSWI fly ash.

We describe a simple method to increase the conductivity of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) film by exposure to ultraviolet (UV) light in vacuum. Up to four order of conductivity improvement (from 10−3 to 50 S/cm) is achieved by irradiating PEDOT:PSS film with 254 nm ultraviolet (UV) light. Increased conductivity in UV treated PEDOT:PSS film is stable under ambient exposure. The mechanism for conductivity improvement is investigated by current-voltage measurement, atomic force microscopy, and absorption spectrum. Photo-cross-linking of PSS chains is determined as the reason for conductivity improvement. Our result demonstrates that UV treatment is capable of modifying the conductivity of PEDOT:PSS film independent of the process of film formation.

The donor/acceptor heterojunction plays an important role in organic solar cells. An investigation of band bending in the donor/acceptor heterojunction is helpful in analysis of the charge transport behavior and for the improvement of the device performance. In this work, we report an approach for detection of band bending in a donor/acceptor heterojunction that has been prepared on a small and sharp tungsten tip. In situ field emission measurements are performed after the deposition process, and a linear Fowler-Nordheim plot is obtained from the fresh organic film surface. The thickness-dependent work function is then measured in the layer-by-layer deposited heterojunction. Several different types of heterojunction (zinc phthalocyanine (ZnPc)/C60, copper phthalocyanine (CuPc)/3,4,9,10-perylenetetracarboxylic bisbenzimidazole, and CuPc/C60) are fabricated and analyzed. The different charge transfer directions in the heterojunctions are distinguished by field emission measurements. The calculation method used to determine the band bending is then discussed in detail. A triple layer heterojunction (C60/ZnPc/CuPc) is also analyzed using this method. A small amount of band bending is measured in the outer CuPc layer. This method provides an independent reference method for determination of the band bending in an organic heterojunction that will complement photoemission spectroscopy and current-voltage measurement methods.

We discuss traditional classroom, e-learning, behavioral engagement and difference between behavioral engagements in two kind of instruction environment. Results from variance analyses suggest that there is no significant difference between engagements of active learning in different classroom conditions, and there exist significant differences on higher-level learning of innovative and critical thinking. Our findings highlight students' behavioral engagements in two environments have no significant advantage over each other, but e-learning facilitates higher-level learning better.