Isolation and Characteristics of New Heterotrophic Nitrifying Bacteria

The study presented the method for isolating the heterotrophic nitrifiers and the characterization of heterotrophic nitrification. When influent Ammonia nitrogen concentration was 42. 78 - 73. 62 mg/L. The average ammonia nitrogen removal rate was 81.32% from the bioceramics reactor. Sodium acetate and ammonium chloride were used as carbon and nitrogen source. The COD removal rates by microorganisms of strain wgy21 and wgy36 were 56.1% and 45.45%, respectively. The TN removal rates by microorganisms of strain wgy21 and wgy36 were 65.85% and 67. 98%, respectively. At the same time, the concentration of ammonium nitrogen was with the removal rates of 75.25% and 84.96%, and it also had the function of producing NO2 - N. Sodium acetate and sodium nitrite were used as carbon and nitrogen source. Through the 12 days of the aerobic culture, the COD femoral rates by microorganisms of strain wgy21 and wgy36 were 29.25% and 22.08%, respectively. NO2 -N concentration decreased slowly. Comparison, similarity of wgy21 and many Acinetobacter sp. ≥99%, similarity of wgy36 and many Acinetobacter sp. ≥99%. Refer to routine physiologicalbiochemical characteristic determination, further evidences showed that wgy21 and wgy36 belong to Acinetobacter sp., respectively.

Biological pretreatment of Yellow River water

Bio-ceramic filter(BF) and moving-bed biofilm reactor(MBBR) were used for biological pretreatment of Yellow River water in this study. The BF only had slight advantage over MBBR for TOC and ammonia removal. However, like UV_ 254 , the average removal rate of THMFP in the BF was much higher than that in the MBBR. UV_ 254 removal did not show obvious correlation with trihalomethane formation potential(THMFP) removal. Hexachlorocyclohexane could be effectively removed in both BF and MBBR. As for diatom and cyanobateria removal the MBBR had better performance than the BF, which was contrary to the average chlorophyll-a(Chl-a) removal rate. The proposal was made in this study that biological flocculation and sedimentation of sloughed biofilm should play a more important role on algae removal in the MBBR than in the BF. The BF and MBBR could effectively remove microcystins. Moreover, MBBR could be a promising technology for biological pretreatment.

Study on the subsonic speed flame spraying coating of hydroxyapatite

A new method of preparation of biomaterial composite coating by the techniqueof subsonic thermal spraying was discussed in this paper. Ti_6Al_4V and pure Ti were chosen assubstrate and sublayer material respectively and the working layer was sprayed with biomaterialhydroxyapatite (HAP), forming the composite coating. The experiments of heat shock and tensilestrength showed that the bonding strength between coating and substrate is almost as same as that ofspecimen in which Ni/Al powder was adopted as sublayer. The phases of TiN, TiO_2, and Ti_2O_3 wereformed in the sublayer, which are free of toxic and have no side effects. The powder of workinglayer HAP was decomposed partly during spraying, but it can be solved by later treatment.

A Research on Hydroxyapatite Front Tooth Implantation

Hydroxyapatite (HA) bio-ceramics implant tooth was tested through animal experiment and clinical application. HA tooth was placed into the fresh extraction socket. At first, HA tooth was chosen and implanted as fixed maxillary front tooth in domestic rabbit immediately after extraction of tooth. Three to six months later satisfactory osseointegration between implanted HA teeth and periodontinum was observed. Clinically, 28 teeth in 25 patients were implanted with suitable HA teeth, chosen according to dental X-ray and models of different kinds of HA dental root. Crowning prosthesis with visible lightsolidfied material made the HA tooth wholesome and nice looking. Implantation and fixation of the HA teeth into the fresh extraction sockets of all the patients were successful.

Fabrication and characterization of the Ti-Ca-P composites by vacuum sintering

Using Ti and biphasic calcium phosphate (BCP) pow-ders, Ti-Ca-P composites which contained 0 - 30 vol.% BCP powders initially, were fabricated by vac-uum sintering at two different sintering temperatures, 1300°C and 1400°C. Detailed microstructural char-acteristics of the resulting composites were investi-gated. Mechanical properties like compressive strength, Vickers hardness were evaluated and they showed decreasing trend with the increasing initial BCP content. The x-ray diffraction (XRD) profiles revealed that extensive chemical reaction occurred and the initial BCP was degraded and formed CaO, TiO2, TiP, CaTiO3. However, the cell viability by MTT assay and cell proliferation behavior through one cell morphology analysis showed excellent in-creasing trend in biocompatibility which makes this materials suitable for hard tissue aid material.And the composite containing 30 vol.% BCP content with Ti sintered at 1400°C showed excellent biocompati-bility with the Vickers Hardness value 108.8 HV and the compressive strength value 303.7 MPa.

Osteogenic and anti-tumor Cu and Mn-doped borosilicate nanoparticles for syncretic bone repair and chemodynamic therapy in bone tumor treatment

Critical bone defects caused by extensive excision of malignant bone tumor and the probability of tumor recurrence due to residual tumor cells make malignant bone tumor treatment a major clinical challenge.The present therapeutic strategy concentrates on implanting bone substitutes for defect filling but suffers from failures in both enhancing bone regeneration and inhibiting the growth of tumor cells.Herein,Cu and Mn-doped borosilicate nanoparticles(BSNs)were developed for syncretic bone repairing and anti-tumor treatment,which can enhance bone regeneration through the osteogenic effects of Cu^(2+) and Mn^(3+) ions and meanwhile induce tumor cells apoptosis through the hydroxyl radicals produced by the Fenton-like reactions of Cu^(2+) and Mn^(3+) ions.In vitro study showed that both osteogenic differentiation of BMSCs and angiogenesis of endothelial cells were promoted by BSNs,and consistently the critical bone defects of rats were efficiently repaired by BSNs through in vivo evaluation.Meanwhile,BSNs could generate hydroxyl radicals through Fenton-like reactions in the simulated tumor microenvironment,promote the generation of intracellular reactive oxygen species,and eventually induce tumor cell apoptosis.Besides,subcutaneous tumors of mice were effectively inhibited by BSNs without causing toxic side effects to normal tissues and organs.Altogether,Cu and Mn-doped BSNs developed in this work performed dual functions of enhancing osteogenesis and angiogenesis for bone regeneration,and inhibiting tumor growth for chemodynamic therapy,thus holding a great potential for syncretic bone repairing and anti-tumor therapy.

Plasma Spray Deposition of HA-TiO2 on β-phase Ti-35Nb-7Ta-5Zr Alloy for Hip Stem: Characterization of Bio-mechanical Properties, Wettability, and Wear Resistance

In this work,a biomimetic coating of hydroxyapatite(HA)-and titania(TiO2)was deposited on low elastic β-phase Ti-35Nb-7Ta-5Zr(β-TNTZ)alloy by plasma spray deposition technique for orthopedic applications.The effect of TiO2 reinforcement on microstructure,mechanical properties,and bioactivity was investigated.The morphology,coating thickness,elemental composition,and phase composition of the developed coatings were characterized.The biomechanical behavior of the deposited coatings was investigated in terms of surface hardness,elastic modulus,and adhesion strength.It was found from the morphological investigation that the TiO2 reinforcement improves the microstructure and prevents the formation of defects in the coating.The biomimetic HA-TiO2 coated surface possessed pores,size ranging from 200 nm-600 nm that benefits the apatite growth and osseointegration.The EDS spectrum,mapping,and XRD analysis show that the deposited layerβ-TCP,CaO,TTCP,TiO2 phases.The HA-TiO2 coating exhibits a very dense and thick layer of 100μm-125am that exhibits excellent adhesion strength to offer mechanical interlocking to prevent delamination.The alloying of TiO2 improves the hardness from 1.67 GPa to 2.95 GPa that enhances the wear resistance.It was found that HA-TiO2 coating exhibits better hydrophilic and biocompatible surface as compared to HA-coating.