铜冶炼厂污水的环保治理——剖析石灰石—石灰两段中和法的技术特点

对大型铜冶炼厂含游离酸较多的污水，采用先投加石灰石乳将污水中游离酸制成石膏；再投加石灰乳去除污水中的铜、锌、砷等重金属离子。同时投加硫酸亚铁，利用铁盐与砷共沉，最终使排放污水中重金属离子含量达到国家排放标准。处理后污水可以重复利用。

糖汁pH值对清汁钙盐含量的影响机理研究

探讨了糖汁清净的加灰 p H值与清汁钙盐含量关系的机理 ,分别导出了 p H值对溶液中碳酸钙、亚硫酸钙、磷酸氢钙含量影响的理论方程和相应的糖汁实验数据回归方程 ,即钙盐含量与其溶液的 p H值呈二次函数关系 .

Effect of hydroxyapatite nanoparticles on the growth and p53/c-Myc protein expression of implanted hepatic VX_2 tumor in rabbits by intravenous injection

AIM： To evaluate the effect of hydroxyapatite nano- particles （Nano HAP） by intravenous injection on the inhibition of implanted hepatic VX2 tumor growth in rabbits and cell p53/c-Myc protein expression. METHODS： 60 hepatic VX2 tumor-bearing rabbits was randomly divided into five groups. Nano HAP collosol 20 mglkg, 40 mg/kg, 5-FU solutions 20 mg/mL, mixed liquor of 5-FU solution 20 mg/mL and Nano HAP collosol 20 mg/kg were infused by vein, normal saline conducted as the control. The general state, weight, liver function and gross tumor volume were detected dynamically. The expression of p53 and c-Myc gene protein in tumor tissue was detected by immunohistochemistry methods. RESULTS： The growth of implanted hepatic VX2 tumors was significantly inhibited in all therapy groups, 3 wk after the injection, the tumor control rates in Nano HAP collosol groups were 25.5% and 32.5% respectively, and the gross tumor volumes were obviously less than that of control group. （24.81 ± 5.17 and 22.73 ± 4.23 vs 33.32 ± 5.26, P 〈 0.05）. The tumor control rate of 5-FU group was 43.7% （18.74 4± 4.40 vs 33.32 ± 5.26, P 〈 0.05）, but the general state of the animals after injection aggravated; and the adverse reaction in the drug combination group obviously decreased. Due to the effect of Nano HAP, the positive expression of tumor associated the mutated p53 and c-Myc in tumor tissue was decreased obviously compared with the control group. CONCLUSION： Nano HAP has evident inhibitory action on rabbit implanted hepatic VX2 tumor in vivo, which may be the result of decreasing the expression of the mutated p53 and c-myc, and drug combination can obviously decrease the adverse reaction of 5-FU.

Mechanical and thermal properties of polypeptide modified hydroxyapatite/poly(L-lactide) nanocomposites

A new type of polypeptide(poly(-benzyl-L-glutamate)(PBLG))modified hydroxyapatite(HA)/poly(L-lactide)(PLLA)nanocomposites(PBLG-g-HA/PLLA)were prepared by the solvent-mixing method,and their mechanical and thermal properties were investigated.The tensile test showed that the mechanical properties of PBLG-g-HA/PLLA nanocomposites were better than that of PLLA,even a 0.3 wt%content of PBLG-g-HA in the nanocomposites could make the tensile strength 12%higher than that of the neat PLLA sample,and the tensile modulus was about 17%higher than that of the PLLA sample.The thermal gravimetric analysis(TGA)showed that the PBLG-g-HA/PLLA composites have better thermal stability than the PLLA sample.The differential scanning calorimetry(DSC)was used to characterize the effect of PBLG-g-HA on the crystallization of PLLA.The isothermal crystallization behavior showed that the half crystallization time(t1/2)of PBLG-g-HA/PLLA was much shorter than that of the PLLA sample.When the PBLG-g-HA content was 10%,t1/2 was only 18.7 min,while t1/2 of the PLLA sample was 61.4 min.The results showed that the PBLG-g-HA worked as a nucleating agent and enhanced the crystallization speed of PLLA.

Repair of radius defect with bone-morphogenetic-protein loaded hydroxyapatite/collagen-poly(L-lactic acid) composite

Objective: To explore the method to repair bone defect with bone-morphogenetic-protein loaded hydroxyapatite/collagen-poly(L-lactic acid) composite. Methods: 18 adult beagle dogs were randomly divided into 3 groups. In Group A, bone-morphogenetic-protein (BMP) loaded hydroxyapatite/collagen-poly(L-lactic acid) (HAC-PLA) scaffold was implanted in a 2 cm diaphyseal defect in the radius. In Group B, unloaded pure HAC-PLA scaffold was implanted in the defects. No material was implanted in Group C (control group). The dogs were sacrificed 6 months postoperatively. Features of biocompatibility, biodegradability and osteoinduction were evaluated with histological, radiological examinations and bone mineral density (BMD) measurements. Results: In Group A, the radius defect healed after the treatment with BMP loaded HAC-PLA. BMD at the site of the defect was higher than that of the contralateral radius. Fibrous union developed in the animals of the control group. Conclusions: BMP not only promotes osteogenesis but also accelerates degradation of the biomaterials. Optimized design parameters of a three-dimensional porous biomaterial would give full scope to the role of BMP as an osteoinductive growth factor.

Preparation and degradation characteristic study of bone repair composite of DL-polylactic acid/hydroxyapatite/decalcifying bone matrix

To explore the preparative method an d study the degradation characteristics of bone repair composite of DL polylac tic acid (PDLLA)/hydroxyapatite(HA)/decalcifying bone matrix (DBM) in vitro. Methods: An emulsion blend method was developed to prepare the composite of PDLLA/HA/DBM in weight ratio of PDLLA:HA:DBM= 1.5 2 : 1 1.5 : 1. The dynamic changes of weight, biomechanical property and pH value of PDLLA/ HA/DBM and PDLLA in phosphate buffered saline (PBS, pH 7.4 ) were studied re spectively through degradation tests in vitro. Results: Without being heated, PDLLA, HA and DBM could be synt hesized with the emulsion blend method as bone composite of PDLLA/HA/DBM, which had both osteoconductive and osteoinductive effects. The diameter of the apertu re was 100 400 μm and the gap rate was 71.3 %. During degradation, the pH v alue of PDLLA solution decreased lightly within 2 weeks, but decreased obviously at the end of 4 weeks and the value was 4.0 . While the pH value of PDLLA/H A/DBM kept quite steady and was 6.4 at the end of 12 weeks. The weight of PDLLA changed little within 4 weeks, then changed obviously and was 50% of its initia l weight at the end of 12 weeks. While the weight of PDLLA/HA/DBM changed little within 5 weeks, then changed obviously and was 60% of the initial weight at the end of 12 weeks. The initial biomechanical strength of PDLLA was 1.33 MPa, decreased little within 3 weeks, then changed obviously and kept at 0.11 MP a at the end of 12 weeks. The initial biomechanical strength of PDLLA/HA/DBM was 1.7 MPa, decreased little within 4 weeks, then changed obviously and kept at 0.21 MPa at the end of 12 weeks. Conclusions: The emulsion blend method is a new method to prepa re bone repair materials. As a new bone repair material, PDLLA/HA/DBM is more su itable for regeneration and cell implantation, and the environment during its de gradation is advantageous to the growth of bone cells.