Advanced Materials Research Vols. 518-523

Abstract: This work describes an approach for the development of two bacteria biosensors based on surface plasmon resonance (SPR) technique. The first biosensor was based on functionalized gold substrate and the second one on immobilized silver nanoparticles. For the first biosensor, the gold substrate was functionalized with acid–thiol using the self-assembled monolayer technique, while the second one was functionalized with silver nanoparticles immobilized on modified gold substrate. A polyclonal anti-Escherichia coli antibody was immobilized for specific (E. coli) bacteria detection. Detection limit with a good reproducibility of 104 and 103 cfu•mL−1 of E. coli bacteria has been obtained for the first biosensor and for the second one respectively.

Abstract: Many types of electrochemical biosensors employ magnetic nanoparticles which have been surface functionalized to recognize specific molecular targets. Here the paper emphatically introduced the operation principle of biosensing magnetic nanoparticles, the overall strategy for fabricating magnetic nanoparticles-based biosensor and the latest application progress in detecting lignocellulase activity and gene expression by electrochemical biosensors.

Abstract: The interaction of soil aggregate with humic substances (HS) is important for fertility and soil carbon sequestration, So it is one of the hot issues of international affairs and Low-carbon Society. In this paper, the pot experiment was conducted to study the effect of the different organic materials on the combined states of humus in black soil. The results showed as follow: Compared with control treatment(CK), application of organic materials significantly increased content of loosely combined in>2mm and content of stably combined, but there was markedly differences among organic materials. Woody residues made loosely and unitedly and stably combined forms of humus in 1-0.5mm aggregates higher than others, at the same time, unitedly and stably combined in 0.5-0.25mm of woody residues were the highest. Animal excrement significantly increased unitedly and stably combined in 2-1mm. And herb residues enhanced stably combined in >2mm obviously. Use of animal remnant resulted in significant increase of tightly combined, whereas markedly decreased tightly combined in 2-1mm. Optical property combined forms of humus varied among organic materials.

Abstract: Distribution of organic matter and effect of wetland types and pH on organic matter were studied in sediment of lakeside belt in east Dongting Lake according to taking 56 samples from surface to 20cm and 52 samples from 20cm to 40cm. The results showed that the average content of organic matter was 15.40g/kg from surface to 20cm and 12.02g/kg from 20cm to 40cm in sediment of lakeside belt in east Dongting Lake. Spatial distribution of organic matter could be expressed as middle variation. Wetland types were classed into silt beach, lake marsh beach and reed beach in Dongting Lake region and influenced distribution of organic matter because of difference variance on hydraulic dynamics condition and retarding effect of vegetation on water flow velocity. Order of organic matter content in sediment was the lake marsh beach > reed beach > silt beach in 0-20cm and 20-40cm layers in lakeside belt in east Dongting Lake. Organic matter contents decreased in turn from 0-20cm to 20-40cm in lake marsh and reed beaches and increased in silt beaches. Values of pH in sediment were slightly alkaline in whole studied region. Negative correlation was established between organic matter content and pH value. The results will provide base data and science reference for controlling and recovery of sediment pollution in east Dongting Lake.

Abstract: The cyanobacteria, salvaged from TaiHu Lake every year, contain high water content and organic matters. Nowadays the problem how to deal with such cyanobacteria has attracted wide attention. In this study, the SCWG is applied to the safety disposal and resource utilization of cyanobaceria to reveal the distributions and forms of carbon, nitrogen and phosphorus in the supercritical products under different reaction conditions. The study results show that SCWG is a good way for the disposal and utilization of cyanobaceria. After SCWG, the C of cyanobaceria exists mainly in the solid residue in the form of coke and heavy oils.High temperature and prolonging reaction time lead to C transfers from s/l phase to gas phase. While N of cyanobaceria is found in liquid phase in the form of NH₃-N, and more than 90% of P can be found in the solid residue.

Abstract: In this paper, the process of cellulase pretreatment before alkali-oxygen pulping of bagasse was studied. The effect of cellulase pretreatment on subsequent pulping was also researched. The results showed that some small-sized components and sugars dissolved into the effluent in the process of cellulase pretreatment. UV spectroscopy showed that there was no significant lignin content in the pretreatment effluent.It was also found that pulping properties were promoted when the cellulase dosage was 2 ECU/g pulp, in that under the same cooking conditions, pulp kappa number was decreased by 1.3 and pulp brightness was increased by 2.5 %ISO, while the viscosity of pulp also increased slightly. Moreover, the tensile index, tear index and folding endurance were increased by 8%, 7% and 30%, respectively, but burst index showed no significant change. The above results illustrated that cellulase pretreatment was only beneficial to the dissolution of sugars and fine components from bagasse and it was an effective method of promoting alkali-oxygen pulping of bagasse.

Abstract: The effect of Fe3+ on the interaction between nitrofurazone (NF) and human serum albumin (HSA) was studied by fluorescence spectroscopy and UV-vis spectroscopy. The results from fluorescence spectra showed that Fe3+ increased the binding constant of NF to HSA, indicating longer storage time of NF in blood plasma. The effect model of Fe3+ was researched by binding distance and the UV-vis spectra, which showed that in the HSA-NF-Fe ternary system Fe-NF complex formed via metal ion bridge and enhanced the binding capability of NF to HSA.

Abstract: The primary hepatocytes of Carassius auratus were incubated with 0, 0.01, 0.1, 1, 10 and 100 mg/l Cadmium(Cd2+) at 25°C for 8h in vitro. The results showed that the hepatocytes survival rate in the 1, 10 and 100 mg/l Cd2+ treated groups were significantly lower than that in the control, the percentage of apoptotic hepatocytes significantly increased in 0.1, 1 and 10 mg/l of Cd2+ treated groups, intracellular reactive oxygen species(ROS) and malondialdehyde (MDA) content significantly increased in 0.1, 1, 10 and 100 mg/l Cd2+ treated groups, typical DNA ladder was observed in 0.1, 1 and 10 mg/l Cd2+ treated groups, and ruleless DNA fragment occurred in 100 mg/l Cd2+ treated group. The activities of the antioxidant enzymes and the expression of their isozymes activities have similar change tendency, compared with the control group, the activities of superoxide dismutase (SOD) and their isozymes were activated by low concentration of Cd2+ (0.1 and 1 mg/l), however, their activities were inhibited by high concentration of Cd2+ (10 and 100 mg/l), especially, the special isozyme (SOD1) was found in the patterns of SOD isozymes in 0.1 and 1 mg/l Cd2+ treated groups, the activities of peroxidase(POD) and its isozymes significantly reduced with a concentration-dependent manner in all Cd Cd2+ treated groups, the activities of catalase(CAT) and its isozymes significantly decreased in higher concentration Cd2+ treated groups (1, 10 and 100mg/l). The results suggested that Cd2+ could damage the activities of the antioxidant enzymes and cause oxidative stress, lipid peroxidation, DNA fragmentation, apoptosis and necrosis in primary hepatocytes, contributing to the liver toxicity induced by Cd2+.

Abstract: The diffusion fluxes of dissolved inorganic nitrogen (DIN) and phosphate (DP) between sediment and water were estimated using Fick’s first law in the area near the sediment dredging location and in the dredged area of Dalian Bay during different seasons. The environmental properties of the studied areas were also investigated. The temperature, pH, dissolved oxygen, and salinity of the bottom water of the two studied areas did not exhibit remarkable differences. The DIN and DP diffusive flux near the sediment dredging area were larger, and the content of organic matters in the sediment was higher compared with the dredged area. In conclusion, sediment dredging induced the accumulation of organic matters in the surface sediment of nearby areas and accelerated the release of DIN and DP from the sediment. Sediment dredging is thus concluded to be among the primary factors contributing to the water eutrophication in Dalian Bay.

Abstract: Methylene blue (MB) was used as model molecule to investigate the effects of surface properties and solvent pH values on the adsorption and desorption (or release) behaviors of mesoporous SBA-15 materials. It was found that the treatment of SBA-15 with a pH 7.8 aqueous solution can enhance the adsorption rate and capacity in comparison with the pristine SBA-15. The effect of pH values on MB releasing from the weak base treated SBA-15 and the pristine one have been studied and been compared in pH values range from 0.5 to 7.0. Both of them showed a maximum releasing rate at about pH 2 and all of the treated SBA-15 samples showed a higher releasing quantity than the pristine ones. The influence mechanisms of base treatment on the adsorption ability and that of pH values on the releasing properties of SBA-15 samples have been analyzed and been discussed based on the composition, the morphology, the surface area and pore size distribution and adsorption/desorption measurements.