Advanced Materials Research Vols. 197-198

Abstract: An injectable calcium phosphate cement (CPC) modified with sodium citrate was developed in the present study. The effects of sodium citrate concentration on the injectability, mechanical strength, and the self-setting properties of CPC were systematically investigated. The addition of sodium citrate significantly improved injectability and compressive strength of CPC. The specimens have an injectability of 93% and compressive strength of 36.43 ± 2.64 MPa at 15 wt% sodium citrate concentration, compared to injectability of 75% and compressive strength of 23.15 ± 2.12 MPa of the specimens without sodium citrate. XRD spectra indicated that addition of sodium citrate did not change the hydration reaction of CPC and the reaction product was mainly poorly crystallized hydroxyapatite. In conclusion, CPC developed in this work exhibited excellent injectability and high strength, which should be a promising material for bone repair.

Abstract: Surface and porous characteristics of spray dried hydroxyapatite microspheres were studied by surface area and pore size analyzer, field-emission scanning electron microscope, Fourier transform infrared spectroscope, etc. The results indicated dehydration did not happened for those samples calcined at 1000°C, and the intensity of OH- absorption bands increased. Hydroxyapatite microspheres were composed of near-spherical crystals with the diameter of 20-50nm. Besides, it was interesting to find that hydroxyapatite crystals formed small aggregate firstly during drying, and then the small aggregate united together and formed particles with spherical structure.

Abstract: Good crystallized Hydroxyapatite was synthesized using H₃PO₄ and Ca(OH)₂ as raw materials by wet chemical method and sintered at 800°C for 3h. The as-prepared HA powders were mixed with 15%, 20%, 25% yttria-stabilized m-ZrO₂, respectively, and sintered at 900°C- 1200°C for 1h, respectively. The main phases and rules of phases changing with the content of yttria-stabilized m-ZrO₂ and sintered temperature was investigated by XRD and the microstructure features of the composite powders were analysed by scanning electron microscopy. The results show that when the temperature is at 1000°C, HA starts to decompose to β-TCP and CaO, the m-ZrO₂ is then partly converted into t-ZrO₂ by partial consumption of CaO, which in turn results in a mixture of β-TCP and HA further. The CaO produced reacts further with m-ZrO2 generating a mixture of t-ZrO₂ and CaZrO₃ in different proportions. The microstructure of the HA-ZrO₂ composite further indicates that when sintered at 1000°C for 1h, gray slice area represent a mixture of HA and a small amount of β-TCP. While in the white area, some spheric ZrO₂ mixed with a negligible amount of CaO. When sintered at 1200°C, distinguished reduced spherical ZrO₂ particles embed within mixed HA and β-TCP, which change from slice to agglomeration. As a result, when the sintered temperature is about 1000°C and the addition of m-ZrO₂ reaches 20wt%, superior main phases are HA and t-ZrO₂, which improves the combination of mechanical and biological properties.

Abstract: A tubal knitted scaffold fabricated from poly(lactic acid) (PLA) yarns was given in this work. The performance of the scaffold during degradation in vitro and the morphology of the scaffold with cells (monkey dermal fibroblasts) were examined. The scaffold fabricated from poly(glycolic acid) (PGA) yarns was manufactured as the control. Results showed that the PLA scaffold could keep much more tensile strength during degradation in vitro, compared with the PGA scaffold. However, cell attachment and proliferation on the PGA scaffold were better than on the PLA scaffold.

Abstract: Rare earth ion-doped Y₂O₃ nanoparticles are attractive for biological imaging applications due to their non-toxicity, resistance to photobleaching, and possibility for upconversion. Y₂O₃:Yb³⁺/Tm³⁺ nanocrystals display photoluminescence (PL) with a peak at ~811nm if excited at ~980nm. This Near-Infrared to Near-Infrared (NIR-to-NIR) upconversion (UC) process provides deeper light penetration into biological specimen and results in high contrast optical imaging due to absence of an autofluorescence background and decreased light scattering. Here, we report that NIR-to-NIR UC PL intensity of Y₂O₃:Yb³⁺/Tm³⁺ nanocrystals are enhanced by doping with different Tm³⁺ ions and Li⁺ ions concentration. When the Tm³⁺ ions concentration reaches 0.25 mol%, the NIR-to-NIR UC PL intensity is the strongest. And the NIR-to-NIR UC PL intensity of Y₂O₃:5 mol % Yb³⁺ ions, 0.25mol% Tm³⁺ ions and 5mol% Li⁺ ions is maximum, which is more that about 14 times than that of no doped Li⁺ ions. This material may show promise for use as probes for biological imaging.

Abstract: 2-((5-mercapto-1, 3, 4 -oxadiazol-2-yl) methyl) benzo[d]isothiazol-3(2H)-one was synthesized and characterized by means of IR, 1H NMR, MS. The compound was tested preliminarily against the bacteria including Escherichia coli, Staphyloccus aurueus, Vibrio alginolyticus, Aeromonas hydrophila and Bacillus subtilis. The results show the title compound has good antimicrobial activity. Isothiazol-3(2H)-ones, 1,2-benzisothiazol-3(2H)-ones, and their heterocyclic bioisomeric derivatives are potent industrial microbiocides with antifungal and antibacterial activities[1,2], highly potent platelet aggregation inhibitor[3], anti-inflammatory, analgedic and anti-pyretic activities[4]. And the biocide 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one is a nonmetallic and nonenvironmentally persistent biocide, which has been registered in several countries as an antifouling agent and has gained approval in the USA and Environmental Protection Agency[5]. Isothiazolones represent a class of versatile intermediates in the synthesis of heterocyclic compounds [6]. According to above facts and the principle of combination of bioactive sub-structure, we herein designed and synthesized benzisothiazolone derivatives2-((5-mercapto-1, 3, 4 -oxadiazol-2-yl) methyl) benzo[d] isothiazol -3(2H)-one, as shown in Scheme 1.

Abstract: Blends of poly (3-hydroxybutyrate-co-4-hydroxybutyrate) [P (3HB-co-4HB)] with poly(L-lactide) (PLA) were prepared by melt-mixing and subsequent injection molding, and their mechanical properties and morphology were investigated. The results show that the tensile properties, impact strength and spherulitic morphology depend strongly on the composition of the blend. The point of transition shows that phase inversion takes place at composition with 40 weight fraction of PLA in the blend.

Abstract: Preparation technology of Zn- peptide complexes was studied and its effects on growth performance and serum biochemical indicators were investigated by feeding Oreochromis Niloticus with feedstuff containing Zn-peptide complexes. The optimal conditions of synthesis reaction for Zn-peptide complexes prepared by zinc with peptide were described in the following: pH 5.0, temperature 80°C, and mass ratio of peptide-Zn 4:1, reaction time 30 min. Under such conditions, yield of Zn-peptide complexes was up to 54%, chelating rate of Zn was 55%, and Zn content of the complex was 6.5×10⁴ mg/kg. A new complex formed from Zinc with peptide was identified by spectrum analysis. The 49-day feeding experiment showed that the complexes remarkably increased specific growth rate, survival rate, content of lysozyme and activity of superoxide dismutase (SOD) and alkaline phosphatase (AKP). Feed conversion ratio was significantly reduced as the additive increased. The content of total protein, albumin, and globulin were elevated too. And growth performance, body immunity, anti-oxidation function of Oreochromis Niloticus was significantly increased while the amount of the additive was 2.4 ~ 4.8 g/kg feedstuff in the experiment.

Abstract: Through the analysis of wood microstructure, the study revealed the reason of forming the wood zone line pattern, and analyzed the wood zone line pattern’s similarities and differences between the artificial cultivation and natural formation. And the wood zone line pattern was formed because that the fungal hyphae invaded into the wood inside. The research results showed that: (1) The causes for the formation of wood zone line pattern, took place when different fungi eroding the same tree, due to antagonism among the hyphae, and the zone line was formed on their against interface. (2) Artificial cultivation and natural formation wood zone line pattern were the same, their hyphae both entered into the wood cells, and formed the irregular, natural and beautiful pattern. The wood zone line pattern could be used as the woodwork surface decoration materials, they were the excellent materials of furniture and indoor decoration. The study laid a theoretical foundation for further research on artificial cultivation fungi coloring wood, really realized the wood biological coloring. And the wood zone line pattern was green, low-carbon, and environmentally friendly products.

Abstract: The method of propagating crack to unfasten bamboo fiber were put forwarded by the authors, and a long bamboo fibers were prepared by this method. The bamboo fiber after fine treatment were tested and investigated .The result shows that: the length of bamboo fiber is 25～ 80cm, the fineness of bamboo fiber is 12～28dtex, the average fracture strength of bamboo fiber reached 5.5 cN/dtex. Its elastic modulus is 3.226GPa.The bamboo fiber has been made by this method could meet initially the requirements of textile fibers.