Advanced Materials Research Vols. 850-851

Abstract: Polygalacturonase (PG) is key enzyme for softening consenescence mechanism of fruits. In this work, Properties of PG separated and purified from wild Actinidia Arguta were studied. The result shows that the optimal reaction temperature is 40°C with a high enzyme activity around 30-50°C. PG keeps a thermo stability at the temperature ranging from 30-40°C, which decreases with increasing of temperature and PG will lose all its activity under 60-70°C for 1h. The optimal reaction pH value for this enzyme is 5.5. As far as the stability in different pH values is concerned, PG is relatively stable for preservation at pH4.5-6.5.The michaelis constant for PG is 27.31. When the concentration for EDTA is higher than 2mmol/L, it is inhibitive for PG . The metal ions of K⁺, Ca²⁺, Fe²⁺, Fe³⁺, Mg²⁺ can activate the PG enzyme to some extent, the strength of activation:Mg²⁺Fe³⁺K⁺Fe²⁺Ca²⁺;The metal ions of Cu²⁺Zn²⁺Mn²⁺Ba²⁺Al³⁺ can inhibit PG enzyme to some extent, the strength of inhibition:Al³⁺Ba²⁺Mn²⁺ Cu²⁺Zn²⁺.

Abstract: Purpose To analyze the biomechanics of cervical spine after one-and two-level Total Disc Replacement (TDR) and two-level Anterior Cervical Discectomy and Fusion (ACDF). Methods Seven adult human cadaveric cervical spines were biomechanically evaluated under eccentric displacement control in six mechanical modes, including flexion (Flex), extension (Ext), left bending (LB), right rending (RB), left rotation (LR) and right rotation (RR). Results In fusion-treated specimens, range of motion (ROM) at instrumented level decreased as much as 81.78%, and other levels also demonstrated big difference in ROM. In arthroplasty-treated specimens, ROM showed little difference from that of the intact state. Large motion variation happened in LB, RB and Ext after both fusion and nonfusion surgical treatments. Conclusions TDR had a more reasonable motion sharing than ACDF, especially in Flex, Ext, LR and RR. No evident influence of motion change was observed after adding an extra level of TDR.

Abstract: The polysaccharides were isolated from the abalone Haliotis discus hannai Ino cultivated from Qingdao and Fujian, and their proliferation activity on HepG2 cell was assessed. The monosaccharide composition of the abalone polysaccharides from Qingdao and Fujian was different, which might be related to their different geographical location and breeding conditions. The proliferation activity of abalone polysaccharide from Qingdao was better than that from Fujian. AAP, AVAP I and AVAP II were further isolated from the abalone polysaccharide from Qingdao, the cell proliferation activity of AVAP I and AVAP II was better than AAP, which might be depended on their monosaccharide composition. Our study would provide preliminary data for the high value utilization of abalone polysaccharides.

Abstract: Objective: To illustrate the relationship between serum HBV-M and HBV-DNA in HBeAg-negative HBV patients. Methods: Serum isolated from HBV patients. FQ-PCR was used to detect the levels of HBV-DNA. ELISA was used to detect the serum HBV-M. Results: The positive rate of HBV-DNA was much higher in HBeAg-positive HBV patients (98.6%) than in HBeAg-negative HBV patients (48.7%). Among the different HBV-M patterns, the positive rate of HBV-DNA with positive HBsAg, HBeAb, and HBcAb was 59.4%; the positive rate of HBV-DNA with positive HBsAg and HBcAb was 32.3%; the positive rate of HBV-DNA with positive HBsAb, HBeAb, and HBcAb was 30.4%; the positive rate of HBV-DNA with positive HbeAb and HBcAb was 13.6%; the positive rate of HBV-DNA with positive HBcAb was 7.7%; the positive rate of HBV-DNA with positive HBsAb and HBcAb was 33.3%. Conclusion: HBV-DNA does still replicate in HBeAg negative HBV patients, and copies of HBV-DNA is a sensitive monitoring marker of monitoring HBV replication for those persons infected HBV.

Abstract: Objective：To study the relationship between the levels of B7-H4 and PBC. Methods：Real-time quantitative PCR were used to detect the levels of B7-H4 mRNA on PBMCs. ELISA were used to detect the serum levels of IL-2. FACs were used to detect the CD4+and CD8+ T-lymphocytes frequencies. Results：Levels of B7-H4 mRNA and B7-H4 frequencies were significantly lower than non-PBC hepatic cirrhosis group and healthy controls (P<0.01). After PHA treated for 72h the frequencies of CD4+, CD8+, and CD4+CD8+ T-lymphocytes were all decreased (P<0.05). The same with serum levels of IL-2 (P<0.05). And the frequencies of CD4+ and CD4+CD8+ T-lymphocytes and serum levels of IL-2 were significantly higher in the PBC group than that of non-PBC hepatic cirrhosis group and healthy controls (P<0. 01). Conclusion：Levels of B7-H4 decreased in PBC and could play an important role in immunoregulation of PBC.

Abstract: About the prediction of the biological damage effects on the lung of human under explosion wave, there are three different criterions, including excessive pressure-impulse criterion, kinematic velocity criterion and specific energy criterion. In the paper, based on the established three criterions and the practical anatomical structure of lung , a new theoretical model on blast lung injury from an explosion is developed. In the present model, the problem of blast lung injury is simplified as the one-dimensional propagation of stress wave in metal foam. Results show that the failure stress of the lung is 0.036~0.072 MPa, and the three criterions can convert to each other.

Abstract: The composition and structure of carbonated hydroxyapatite (CHA) are much closer to those of inorganic minerals in natural bones. A series of experiments have been conducted to investigate the following aspects: (1) the mechanism of CHA synthesis by precipitation approach; (2) the biocompatibility and stability of CHA coatings. The results showed that an even single phase CHA crystals could be developed from Ca (NO)₃-(NH₄)₂HPO₄-NaHCO₃-NH₄OH system. Lastly, the surface of Ti-based CHA/UHMWPE coatings (2μm) was uniform and continuous with average bond strength of 32 MPa. 60 days after implanting the coatings into animals, the surface of the implanted material was totally covered by newly grown bone tissues whose structure was of no significant difference with normal bones, without changing coatings bond strength greatly. The result of the present work implied CHA coatings have excellent bioactivity and stability.

Abstract: Flume experiments were conducted to assess the impact of defined local hydrodynamic conditions on the growth process of periphytic biofilm. Biofilms were developed in four different local hydrodynamics with friction velocities of 0.0027, 0.0064, 0.0117 and 0.0172 m/s respectively over a 36-day period. The initial colonization of microbial community was significantly delayed by high flow velocities. The dry mass, bacterial abundance and total EPS content of biofilms reached their maximal values at a critical friction velocity of 0.0064 m/s, as a result of the conflicting effects of mass transport and shear stress from local flow fluid. The results indicated that local hydrodynamics during periphytic biofilm growth conditioned the structure and composition of biofilms.

Abstract: The classification and mechanism of the biofilm for treatment wastewater were introduced in this paper. Bio-contact oxidation, a typical biofilm process was described in detail. The example of treatment sewage of Heilongjiang University of science and technology proved that bio-contact oxidation process was more efficient for treatment sewage. It was considered as a wide range of application prospects.

Abstract: Gene expression profiles of tumor have the limited amount of samples in comparison to the high dimensionality of the samples;this paper proposed a classification algorithm based on neighborhood rough set to improve classification accuracy.This paper first applied feature filtering method of kruskal-wallis rank sum test to select a set of top-ranked related genes, and then applied neighborhood rough set on these genes to generate a informative genes subset. Finally, SVM was used to classify the GEP data set. The result of the experiment indicates that this method can effectively improve classification accuracy, and it has higher generalization.