Advanced Materials Research Vols. 183-185

Abstract: Hydrolyzed collagen prepared from Tilapia scale with Alcalase and Papain after decalcificated in HCl and demineralized in Ca (OH)₂. Hydrolyzed collagen with the content of 1%, 2%, 3%, 4%, 5% was added to the bread to research the sensory valuation, properties and texture of bread. And then the properties of bread during storage were evaluated. Results showed that the addition of collagen peptides improved the water retention of bread, increased bread specific volume and slowed down the staling of bread. Comprehensive comparison, the quality of bread reached optimum with 3% of hydrolyzed collagen.

Abstract: Hosta undulate, Hosta plantaginea and Hosta plantaginea ‘Rosea’ were introduced to Harbin to evaluate the cold resistance compared to Hosta ventricosa stearn which can survive during the winter in Harbin. The physiology characteristics of Hosta species were determined under ground conditions. Along with the temperature drop, the increase of relative conductivity and MDA content of Hosta undulate were lower than Hosta plantaginea and Hosta plantaginea ‘Rosea’. Whereas contents of soluble sugar and free praline of Hosta undulate were higher than these two Hosta species. In view of the minimum temperature of winter in Harbin, chilling tolerance were conducted at -35°C and -40°C for 3h, 6h and 9h. Hosta undulate shows outstanding cold resistance and recovery growth.

Abstract: Ferrum is one of the important nutrient sources for algae in lakes. The changes of concentration in water body have great effect on the formation of dominant algae. Microcystis aeruginosa, Scenedesmus quadricauda and Cyclotella were examined in M11 culture medium which included different Fe²⁺ and Fe³⁺ concentration. Growth curves of these three algae were fitted by logistic growth-model, respectively. The maximum biomass K, inflection t and growth rate µ of those algae were investigated. The effects of Fe²⁺ and Fe³⁺ on the growth of algae were investigated by using the Monod equation. The semi-saturation constants were calculated. The results showed that the maximum biomass of these three algae did not increase with the increasing of Fe²⁺ and Fe³⁺ concentration. Low concentration of Fe²⁺ (200-500 mg/L) and high concentration of Fe³⁺ (2000-5000 mg/L) were more suitable to the growth of three algae. The sequence of the maximum biomass was: Scenedesmus quadricauda>Microcystis aeruginosa>Cyclotella.

Abstract: Fenton and Fenton-like reactions are regarded as high efficient methods in advanced treatment of nitrobenzene wastewater but both restrained in degradation of nitrobenzene in groundwater because of the low pH condition( less than 4 ) requirement and other problems such as secondary pollution by the irons in contaminated sites. This paper reports a new Fenton-like technology combined irons extraction from aquifer materials which were found in a nitrobenzene contaminated site in China with hydrogen peroxide catalytic oxidation. The simulate experiments were conducted to investigate the oxidation of nitrobenzene in groundwater by this method under the condition of neutral pH and 8~10°C. The comparison of different extraction agent and production rule of hydroxyl radical were both studied in this research. The results indicated that extraction had hysteresis property because the highest extracting efficiency occurred after 36h. Extraction agent DCB has the highest efficiency, for Fe³⁺ was 62.92% and Fe²⁺ was 30.17%. The highest removal efficiency could reach 80.2% while the mole ratio of nitrobenzene to H₂O₂ was 1:200. Three stages could found in hydroxyl radical generation process, in the first stage hydroxyl radical generated rapidly in 0~30min, then decreased slowly between 30min and 120min, at last the generation tended to be steady after 120h. The results could possess a good potential for application in the treatment of nitrobenzene contaminated groundwater and provide theoretical basis on in-situ chemical remediation technology of nitrobenzene contaminated sites.

Abstract: During the process of cultivation of salt-tolerant nitrifying bacteria, the increase in NaCl concentrations was carried out in two different manners. The NaCl concentration in reactor A was increased by increment of 5 g/L, while the NaCl concentration in reactor B was increased by increment of 2.5 g/L. The impacts of NaCl content on the fresh culture and two acclimated cultures were investigated, which focused upon the changes of the specific ammonium oxidation rate (SAOR) and specific nitrite oxidation rate (SNOR). The results indicated that fresh nitrifiers were severely inhibited by high salinity. At NaCl concentration of 25 g/L, ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) completely lost the nitrification capability. After 46 days of acclimation, the nitrifying bacteria could be adapted to the saline wastewater. The average SAOR and SNOR in reactor B were slightly higher than those in reactor A, which meant that low increment in salt concentration may be in favor of the development of salt-tolerant nitrifiers. But the two NaCl increasing approaches did not affect the SAOR and SNOR too much. Salt-tolerant nitrifiers could be well developed with the two acclimation manners.

Abstract: Concentrations of selected heavy metals (Cd, Cu, Pb, Cr and Zn) were determined in vegetables (radish, tomato, gourd, celery, lettuce, Chinese lettuce, Garland chrysanthemum, rape, Chinese cabbage, Sonchus) from the wastewater irrigation area in Tianjin, China. Cd contents in the edible parts were not significantly different among all vegetables. Zn concentration in the leafy vegetables was the highest of all the heavy metals. The metal contents in the vegetables were compared with the Chinese national standards for food quality. The contaminant index of Cr, Pb, Cd and Zn varied respectively between from11.96 to 22.26, from 5.36 to 14.43, from 0.95 to 15.4 and from 0 to 4.06. Although Cu content of the vegetables except lettuce was lower the permitted standard, the results indicated these vegetables could not be regarded as safety for human consumption.

Abstract: Each of us are exposed to the environmental electromagnetic fields, such as the geomagnetic field, electromagnetic field from power line, and antenna radiation etc. all the time, when the biological tissue exposure in the electromagnetic fields may lead some certain effects, and many effects are studied during the past few years, most of these studies concentrated on negative effects of electromagnetic fields. It is necessary to explore effects of these environmental electromagnetic fields on human body comprehensively, some effects of environmental electromagnetic fields are studied theoretically in the following paper, and attenuate characteristics of several environmental electromagnetic fields propagate in human body is discussed. The theoretical results expressed the penetration depth of several environmental electromagnetic fields, and the possible effects of long term effects are analyzed.

Abstract: Bioavailability of polycyclic aromatic hydrocarbons (PAHs) has an impact on its bioremediation and environmental risk assessment. Bioavailability was affected by contaminated time, soil properties and pollutant properties. In this study, the effect of soil properties on bioavailability of phenanthrene (Phe) to earthworm was investigated. The results showed that the bioavailability to earthworm varied with soil properties. Regression analysis results showed that bioavailability of PAHs had a negative correlation with soil organic matter content, clay and cation exchange capacity (CEC) and positive correlation with pH. Conclusions of the study can be used for references to remediate the PAHs contaminated site.

Abstract: The important premise for hydrogen production technology of fermentation generator was to separate and identify the efficient hydrogen producing bacteria. By use of Hungater technology and flat-panel technology with wide-body narrow-neck flask, LM-1 and HPB-LR medium to separate and identify the anaerobic fermentation hydrogen production bacteria, and five hydrogen-producing bacteria were obtained, whose hydrogen metabolism was ethanol fermentation. The product analysis on the hydrogen production bacteria fermentation liquid showed that ethanol and acetic acid accounted for 95%-99% of the total metabolites. These strains can be fermented to produce hydrogen, and can be used for industrial applications.

Abstract: A label-free amperometric immunosenor for determination of anthracene was developed. Prussian blue was electrodeposited on the glassy carbon electrode and then modified with nanometer-size gold film to protect Prussian blue layer and immobilized anthracene polyclonal antibodies. The characteristics of the modified electrode at different stages of modification were studied by cyclic voltammetry. The performances of the amperometric immunosensor were studied in detail. At the optimal experimental condition, the current response of the immunosensor was proportional to the concentration of anthracene in the range of 1.8~90 ng•mL^-1 with a detection limit of 0.82 ng•mL^-1 (S/N=3). The studied immunosensor exhibited low detection limit, long-term stability and easy regenerated. This mothod was applied to the anthracene detection in river water samples with satisfied results.