Applied Mechanics and Materials Vols. 138-139

Abstract: Aimed at the current problems of capacious of hydrotreater, susceptible to plugging by microbe and the accumulation of ammonia or nitrite nitrogen in aquaculture, the aquarium (contain with the water treatment processor) using physical filtration + biodegradation + activated carbon adsorption complex process was devised to treat aquaculture for recycle. Under different working conditions, the effects of water temperature, hydraulic retention time (HRT), air flow and aeration mode on removal efficiency of ammonia, nitrite nitrogen and nitrate nitrogen (three nitrogen) in aquaculture. The test results showed that sludge yielding in the hydrotreater was low and hydrotreater was insusceptible to be plug. In addition, under the conditions of water temperature 25°C, air flow 1.5L/min,HRT 1.5h and intermittent aeration (aerating once every 1h), the removal rate of ammonia nitrogen , nitrate nitrogen and nitrite nitrogen was over 97.5% ,96% and 98.7% respectively, it means the three nitrogen was not detected. Therefore, the incorporated aquarium could permanently preserved favorable living environment for fish and could provide technological security for three nitrogen remove of fish farm water and for intensifying water recycle.

Abstract: The structural and electronic properties of alkannin and its derivatives and their radicals were investigated at density functional level. It turned out that the presence of the dihydroxy functionality increases the radical stability through hydrogen bond formation and favors hydrogen atom abstraction. The introduction of electron-donating groups for the molecules increases the activities of antioxidants. Moreover, alkannin and its derivatives appear to be good candidates for the one-electron-transfer mechanism. Their extended electronic delocalization between adjacent rings determines low ionization potential (IP) values, and it can be further improved by the introduction of the electron-donating groups for the molecules.

Abstract: Heart rates and breathing rates are widely used to assess the health state of human in clinic. Tranditional method uses eletrodes or sensors touching the body to measure electrocardiography (ECG) and respiratory signals.A vital signs monitor via a micorwave sensor was disscused to contact-free measurement of the heart rate and breathing rate. Comparison of vital signs derived from the microwave sensor and tranditional contact monitor demonstrated that there were no significant differences between each other, which suggested the contact-free vital signs monitor may prove a practical alternative method to measure heart rate and breathing rate.

Abstract: This paper explains how the Lignin peroxidase and Manganese Peroxidase from Coriolus Versicolor were co-immobilized by chitosan microspheres.It studies kinetic character of the enzyme after co-immobilization.Optimum Lip and MnP activity obtained at 30-35°C for 14 hours in pH 8.4 glutaraldehyde solutions during immobilized to chitosan microspheres which prepared by coagulation in NaOH: methanol=3:2. When kept at 50°C for 6h, more than 80% of the immobilized enzyme activity remained, while the free enzymes were inactive under the same conditions. The co-immobilized enzyme can remain 70% activity after two weeks while both of the free enzymes inactive. Compared with the free enzymes, temperature and time stability of the co-immobilized enzyme was considerably improved.

Abstract: A phenolic copolymer was synthesized from resorcinol (RSC) and 3,5-dihydroxy benzoic acid (DBA) using horseradish peroxidase (HRP)/H₂O₂ as the radical copolymerization’s initiateor. It was discussed that the effects of monomer composition on the properties of the copolymer. The best molar ratio was 1:1. The structure and properties of the copolymer was characterized by Fourier Transform Infrared spectroscopy (FTIR) and Nuclear Magnetic Resonance (HNMR), Molecular weight (M_W) was determined by gel permeation chromatography (GPC). The result shows that the average molecular weight of the copolymer is about 40000. The effect of dosage of HRP on the properties of the copolymer was investigated. And the mechanism of polymerization of RSC and DBA was advanced. The copolymer was used as tanning agent, applied results show that it has excellent retanning properties. It was realized the applicatiom of HRP on the phenols syntan.

Abstract: Objective: To observe the effects of chemosensitizer on expression of P-glycoprotein (P-gp) in multidrug-resistant (MDR) carcinoma cells and the changes of corresponding ⁹⁹Tc^m-MIBI (referring to methoxy isobutyl isonitrile) uptake kinetics. Methods: Firstly, the immunocytochemistry was used to test the experssion level of P-gp in carcinoma cells; then the γ counter was used to test the uptake rate of radioactive precipitation of ⁹⁹Tc^m-MIBI; and finally to do statistical analysis of the test data. Results: The P-gp expression in MCF-7/S cells was negative, while it was strongly positive in MCF-7/ADM cells, and the P-gp expression in MCF-7/ADM cells reduced significantly after the tetrahydropalmatine (Tet) effect. The uptake rate of MCF-7/S cells reached the maximal value (1.39%) after being cultured with ⁹⁹Tc^m-MIBI for 90 minutes, and then it kept in equilibrium. The ⁹⁹Tc^m-MIBI uptake rate of MCF-7/ADM cells had been maintained at low level, being 0.371% after 90 minutes. The ⁹⁹Tc^m-MIBI uptake rate of MCF-7/S cells was higher than that of MCF-7/ADM cells. After the tetrahydropalmatine and verapamil effects, the ⁹⁹Tc^m-MIBI uptake rate of MCF-7/S cells had no significant change, while the ⁹⁹Tc^m-MIBI uptake rate of MCF-7/ADM cells increased by 1.9 times. Conclusion: Tet can reverse the MDR in MCF-7 cells, and the mechanism can achieve the effect of reversing the drug resistance through adjusting down the expression of P-gp in carcinoma cells.

Abstract: The effects of different etching temperatures (near room temperature) on the length and surface morphology of SiNWs were reported in this paper. The studies on temperature dependence of SiNWs growth rate were carried out at 20 °C, 30 °C, 40 °C, 50 °C, 60 °C, and 70 °C for n-type and p-type substrates. The results suggested that the SiNWs length could be controlled easily by the change of the etching temperature. Superlong SiNWs were also fabricated by this technique. The superlong SiNWs had the length more than 400 μm and the aspect ratios were about 2000-20000, which could be applied in nanosensors and interconnection.

Abstract: Superparamagnetic iron oxide (SPIO) nanoparticles were used more and more universally in biomedical research recently. In order to develop a suitable immuno-magnetic probe which can be applied in antigen-antibody based immunoassay, such as tumor marker or cardiovascular marker detection, SPIO capped by dextran was synthesized with chemical coprecipitation method. With sodium periodate method, hydroxyl groups of dextran were oxidated to aldehyde groups, thus conjugated with antibodies by covalent bonds. Western blot pattern illustrated that structure integrity of the most antibodies was kept well, harmful influence given by oxidation of conjugation was very finite. Both immune reactivity and antigenicity of antibodies in the SPIO based immunoprobes were retained effectively. This probe has a potentially application in SPIO based novel suspension array for its superparamagnetic property that can be separated under gradient magnetic field.

Abstract: Research on automatic sleep staging based on EEG signals has a significant meaning for objective evaluation of sleep quality. An improved Hilbert-Huang transform method was applied to time-frequency analysis of non-stable EEG signals for the sleep staging in this paper. In order to settle the frequency overlapping problem of intrinsic mode function obtained from traditional HHT, wavelet package transform was introduced to bandwidth refinement of EEG before the empirical mode decomposition was conducted. This method improved the time-frequency resolution effectively. Then the intrinsic mode functions and their marginal spectrums would be calculated. Six common spectrum energies (or spectral energy ratios) were selected as characteristic parameters. Finally, a probabilistic nearest neighbor method for statistical pattern recognition was applied to optimal decision. The experiment data was from the Sleep-EDF database of MIT-BIH. The classification results showed that the automatic sleep staging decisions based on this method conformed roughly with the manual staging results and were better than those obtained from traditional HHT obviously. Therefore, the method in this paper could be applied to extract features of sleep stages and provided necessary dependence for automatic sleep staging.

Abstract: In this article, the distributions of droplet nuclei with pathogens which was evaporated from the droplets released by cough was and trace gas CO₂ were compared to study the airborne characteristics of droplet nuclei. The infectious isolation room model with steady particle source model was built. The particle source was built according to the size distribution of the droplet nuclei with pathogens which was evaporated from the droplets released by cough. The CO₂ source was build at the same location with the particle source and released in the same way. The simulation result showed that the distributions of droplet nuclei and CO₂ which were simulated by CFD were similar under the same ward airflow. This proved that these droplet nuclei could suspend in air and move with airflow. it was feasible to use tracer gas CO₂ as trace gas to solve the validating the numerical simulation of droplet nuclei distribution in infectious isolation room.