Advanced Materials Research Vol. 900

Abstract: In order to improvedβ-TCP biocompatibility and cell growth, was chosen to modify β-TCP matrices to produce a γ-PGA/β-TCP composite biomaterial. Then, the morphology, water uptake and retention abilities, in vitro degradation property in the simulated medium, cytotoxicity of this novel γ-PGA/β-TCP composite is investigated. SEM shows that the γ-PGA/β-TCP composite has a porous structure. By increasing the percentage ofγ-PGA from 0% to 50%, the swelling ratio of the composite s was enhanced from 9.0%to 297%. These data suggested that the surface hydrophilicity, water absorption rate, and swelling ratio were improved by adding γ-PGA to the composite. In the cytocompatibility test, the density of MC3T3-E1 preosteoblasts cells on the PTCP1:1 leachates was almost 110% higher than that on the controls on day 3. Therefore, the γ-PGA/β-TCP composite scaffolds, due to their better hydrophilicity, cytocompatibility, and porous structure, are very promising biomaterials for tissure engineering applications.

Abstract: A azamacrocyclic compound with carboxyl branch, 5,5,7,12,12,1-hexamethy-1,4 ,8,11-tetraazacyclo- tetradecane-N/-acetic acid(L), and its neodymium complex ware synthesized and characterized. The mode of combination of the neodymium complex with DNA was investigated by UV-vis absorption spectroscopy methods. The cutting function of the neodymium complex to supercoiled DNA was studied by gel electrophoresis method. The results show that metal complex can bind to the phosphate of DNA double helix and promote the hydrolysis of phosphodiester bond of supercoiled DNA(Form I); Supercoiled form DNA was transformed into nicked form DNA(Form II) with strong cutting effect of the macrocyclic neodymium complex; the reaction of DNA cut is completed by a hydrolysis mechanism.

Abstract: In this thesis, aperiodic genomic DNA have weak charge transfer; the transmission coefficient of DNA with short period sequence does not seem to depend on the length, yet differently, the transmission pattern of aperiodic genomic DNA sequences strongly depends on the strand length. As the number of corresponding bases increases, fewer states will present good transmission ability, because aperiodic increasing bases make more backscattering; at low temperature, the transmission spectrum presents a higher number of transmitting states, due to a breaking of level degeneracy. At higher temperature, the number of transmitting states decreases; Small intrastrand hopping integral does not seem to diminish the transmission coefficient, but shrinks the location in the three-dimension figure. And the distribution of energy is concentrated.

Abstract: In this work a preliminary study on the physical properties and antimicrobial activity of environmentally friendly active films to be produced is presented. Chitosan (CH), which has antimicrobial effect on many food pathogens, was coated as antimicrobial agent into composite poly (lactic acid)/poly (ε-caprolactone)(PLA-PCL) films. Antimicrobial active films based on PLA-PCL were prepared by coating five different chitosan concentrations: 0, 2, 4, 6 and 8 %(w/w). The mechanical characterization, water vapor permeability (WVP), and antimicrobial activity of composite PLA-PCL film coating with chitosan were carried out. The mechanical characterization, water vapor permeability of composite PLA-PCL films coating with chitosan was uninfluenced. Antimicrobial activities of films were tested against Staphylococcus aurous, Escherichia coli, Bacillus subtilis, Listeria, Salmonella. The antimicrobial activity of films were significantly increase with the chitosan concentration. The results of this work suggest that chitosan coated composite PLA-PCL films have a prospectively potential in antimicrobial activity food packaging.

Abstract: We have performed density functional theory calculations on the alkaline hydrolysis of diethyl p-chlorophenyl phosphate and triethyl phosphate in the gas phase and in solution. It is found that the two hydrolysis reactions proceed through associative mechanism. The second step of hydrolysis reaction has a very low energy barrier fro diethyl p-chlorophenyl phosphate. For triethyl phosphate, the free energy barrier for the second step is higher both in the gas phase and in solution, indication the second step is the rate-determining step. The free energies of all stationary points and the free energy barrier for all the processes in solution are higher than those in the gas phase. Our calculations provide a comprehensive data set and allow re-interpretation of previous experimental and theoretical studies, and new experiment is proposed to trace reactions both in the gas phase and in solution.

Abstract: Near-stoichiometric lithium tantalite (LiTaO₃) crystals were grown by the top-seed solution pulling method in congruent melt with the addition of K₂O. The crystals were characterized by measurement of the ultraviolet absorption edge, ability of photo-damage resistance, and the domain structure analysis. Compared with the congruent crystal shows that, the ultraviolet absorption edge of the near-stoichiometric crystals has a blue shift towards a shorter wavelength and curie temperature is also improved; the domain structure of near-stoichiometric LiTaO3 crystals is hexagonal; and the photo-damage resistance of the crystals is greatly improved.

Abstract: Magnesium hydroxide was prepared through direct precipitation using magnesium chloride and ammonia as raw materials. In this paper, we mainly studied the effects of magnesium hydroxide on product characterization when the concentration of raw materials was changed. The products were characterized through laser light particle size analysis, scan electron microscope and X-ray diffraction. The study showed that a sudden change in the morphology of magnesium hydroxide products and in the polarity of the crystal occurred under the following conditions: stirring speed of 2500 rpm, reaction temperature of 60°C, ammonia to magnesium chloride ratio of 2:1, ammonia addition rate of 20 mL/min, and aging time of 30 min. As the raw material concentration was changed, the morphology of magnesium hydroxide products and the polarity of the crystal exhibited sudden change. When the concentration of magnesium chloride was changed to 0.8 mol/L, the product demonstrated a flower-like globular structure, the largest size, and the minimum polarity. When the concentration of magnesium chloride was more than 1 mol/L, the product exhibited a flake structure, no obvious aggregation and a narrow particle size distribution.

Abstract: Cotton fabric and hemp fabric belong to the natural cellulose fibers, different in molecular structures and fiber properties, but similar to the main chemical properties.Mechanism of their reactive dyes are the same, dyeing property and rate are similar.Therefore cotton/hemp fabric using one-bath one-step dyeing with reactive dyes can shorten the dyeing process, technology is feasible to achieve.

Abstract: A method to make a kind of printing ink cleaning solution is studied in plateaus. At present, any applicable lithographic printing ink cleaner solution can wash the ink in plains, but not applicable in plateaus which are under low pressures. A kind of lithographic printing cleaning solution is made in this paper, which can solve the problem of volatilizing fast and being not clear. The solution we made have a good cleaning effects, which will not make ink rollers transformed, and not have any injury to PS plate. It will satisfy the condition under the climate of plateaus.

Abstract: Electrochemical polymerization is an effective method for the preparation of conductive polymer materials. BFEE solutions are used in preparation of various high-performance conductive heteroaromatic polymers materials as mixed electrolytes, and BFEE can effectively reduce the oxidation potential of monomer. This paper reviews the research on electrochemical polymerization of heteroaromatic polymers with BFEE mixed electrolyte solution in recent years, and prospects the further development direction and application of the electrochemical polymerization of heteroaromatic polymers.