Advanced Materials Research Vols. 197-198

Abstract: The need for a topical drug delivery system of griseofulvin (GF) is dued to its poor oral bioavailability because of its low water solubility and excessively side effects. The preparation of griseofulvin-loaded into solid lipid nanoparticles (GF-SLNs) to nanometer range is expected to improve the dissolution rate by increasing the specific surface area. The aim of investigation was to produce griseofulvin-loaded into solid lipid nanoparticles by using a simple microemulsion technique, using glyceryl monostearate as solid lipid, polysorbate 20 as emulsifier, butanol and Transcutol HP^®as co-emulsifiers. The GF-SLNs were evaluated for physical and chemical properties including GF release from GF-SLNs. The spherical particles were observed by TEM. The mean particle size of GF-SLNs was 165 nm and the zeta potential of GF-SLNs was -36 mV. There were interactions between GF and excipients in formula. The GF releasing profiles were obtained by a dialysis method with pH 5.5 phosphate buffer as medium, the release profile of GF was to be a prolong release of 63.53% within 12 hours.

Abstract: N-2-hydroxyethyl-glucamine (NHEG) was converted into 6-deoxy-6-hydroxylethyl-amino-L-sorbose (DHES) by the regioselective oxidation of Gluconobacter oxydans, and then the generated intermediate of this process was produced to N-hydroxyethyl-deoxynojirimycin (Miglitol) by reductive ring closure reaction. Regioselective oxidation reaction was catalyzed by the high activity sorbitol dehydrogenase of Gluconobacter oxydans biomass which was obtained in preliminary studies. Reductive ring closure reaction was carried out under the conditions of 10%Pd/C as catalyst, at 45~55°C and 0.6MPa of hydrogen. Reaction mixture by the separation and purification of strong acidic exchange resin column has been the Miglitol. In addition, the structure and properties of synthetic product was characterized by thin layer chromatography (TLC), melting point, mass spectrometry (MALDI-MS), Fourier transform infrared spectroscopy (FTIR) analysis. The results showed that the miglitol yield is 77.3%.The regional specificity of the high activity sorbitol dehydrogenase of Gluconobacter oxydans has been verified. Moreover, combinating the technology of the Pd/C- catalyzed reductive ring closure reaction, an effective synthesis process of miglitol is achieved.

Abstract: This paper investigated the microstructures and compressive properties of hot-rolled Mg-Zr-Ca alloys for biomedical applications. The microstructures of the Mg-Zr-Ca alloys were examined by X-ray diffraction analysis and optical microscopy, and the compressive properties were determined from compressive tests. The experimental results indicate that the hot-rolled Mg-Zr-Ca alloys with 1% Ca are composed of one single a phase and those alloys with 2% Ca consist of both Mg₂Ca and a phase. The hot-rolled Mg-Zr-Ca alloys exhibit typical elongated microstructures with obvious fibrous stripe, and have much higher compressive strength and lower compressive modulus than pure Mg. All the studied alloys have much higher compressive yield strength than the human bone (90~140 MPa) and comparable modulus with the human bone, suggesting that they have a great potential to be good candidates for biomedical applications.

Abstract: One key step for silk protein further uses is to let them be dissolved in aqueous solution. However, the silk protein is usually not soluble in aqueous solution. Silk protein dissolved in calcium chloride solution is one of the few effective ways. Silk fibroin was well dissolved in 15-20min. in boiling calcium chloride solution [50% (w/v)] with the ratio of 15g dry waste silk per100mL calcium chloride solution. After dialysis, silk protein calcium salt unexpectedly showed excellent emulsification capacity and stability. Only 0.8-1.2% of silk protein calcium salt solution (50mL) could let 50mL soybean salad oil be mixed and emulsified well. Silk protein calcium salt may be used as a new protein-based surfactant.

Abstract: An aminated D-glucose [N,N'-di-b-D-glucopyranosyl ethylenediamine] was prepared and thoroughly characterized by FT-IR, ESI-MS, NMR spectra and elemental analysis. Compared with D-glucose, the FT-IR spectrum of the aminated glucose showed a moderate peak at 1629~1608 cm^-1 which was attributed to dNH vibration, suggesting glucose reacted to ethylenediamine (en). The ESI-MS spectrum exhibited a strong peak at m/z 383.2, which was assigned to the species [C₁₄H₂₇O₁₀N₂]^-. The ¹H-NMR spectrum of the aminated D-glucose demonstrated the signal of the C₁ proton and the amino proton at 4.82~4.79ppm, illustrating the amino of ethylenediamine was substituted for the hydroxy group of C₁. As for UV spectra, the aminated glucose hadn’t absorbance in the ultraviolet region while its complex with Cu²⁺ had obvious absorption peak at about 236nm. The complex ratio of the aminated glucose to Cu²⁺ was close to 1:1 and the stability constant of its Cu²⁺ complex was 6.8*10⁷ in 0.01mol×L^-1 borax buffer solution.

Abstract: Abrasive flow machining (AFM) is an effective way to the irregular surface and internal structure of parts polished, debarred, filleted finish machining and so on. Presently abrasive flow machining is primarily applied for aviation, aero-plane in China, but it hasn’t been used widely. Because there are still many technical problems to be solved, such as: the studies on AFM equipment, preparation of abrasive and cutting mechanism. In order to further improvement of AFM technology, a lot of experimental research should be done. In this paper, by Pro/E design for the experimental device, and by ANSYS analysis of mechanical properties, and finally the test device can be verified to meet the test requirements, and achieve the test successfully.

Abstract: Hydroxyapatite (HA) doped with 3% Yttria-stabilized 20vol%m-ZrO₂ composite were synthesized by solid state reaction between tricalcium phosphate (TCP) and Ca(OH)₂ at various temperature(1000 to 1200°C) for 3h with adding 5~20wt% calcium fluoride (CaF₂), respectively. The effects of various amount of CaF₂ on crystallization characteristics of HA-20vol%ZrO₂ composite were investigated in details. The results show that when small amount of CaF₂ was added, the reactions of HA with CaF₂ occurs, which leads to the formation of fluorapatite (FA). With the increasing of the amount of CaF₂, the decomposition of HA to β-TCP decreases gradually and the CaZrO₃ peaks disappear, while t-ZrO₂ increases because of the formation of thermally stable FHA solid solutions. When the sintered temperature is above 1100°C and the addition of CaF₂ is about 10wt%, the main phases are FHA and t-ZrO₂ with a negligible amount of Ca₅P₈, which suppress the reaction between HA and ZrO₂. From SEM, it can be seen that with 10wt% of CaF₂ addition, the morphology of the composite powder is a mixture of spherical ZrO₂ particles embedded within agglomerated HA shaped like a small rod.

Abstract: Garlic fructan (GF) is one of the main components of garlic (Allium sativum L.) and has been largely produced from the residue discharged from getting essential oil in China. Some GF characteristics of the related food engineering, such as solubility, oil absorbability, foam ability, moisture absorption and retention, thermal and acidic stability and the like were investigated. Results showed that GF was soluble in water, slight soluble in ethanol but insoluble in acetone, ethyl acetate or butanol. The precipitation increased as the concentration of alcohol rise. GF presented better oil absorption than casein, as well as higher capacities of moisture absorption and retention in humid and dry environment than glycerin, but lower frothing and foam stability than egg white. GF was not stable at the environment of high acid and temperature. These results provide foundation for the application of GF in liquor, fat substitute food, chemical medicine and other use.

Abstract: Wool fiber shows a natural crimp morphology, which endows textiles made of wool fiber with good elasticity and warmth-retaining performance. The natural crimp of wool fiber is due to the difference of the hierarchic structure of ortho-cortex and para-cortex of wool fiber. The present study investigated the fractal structure of ortho-cortex and para-cortex in detail to provide a new interpretation for the reason why the wool fiber has a natural crimp morphology and good performance in textiles.

Abstract: In this study the effect of heat treatment on some physical properties of Douglas fir (Pseudotsuga menziesii) was investigated. Wood specimens were subjected to heat treatment at 160, 180, 200 and 220°C for 1, 2, 3 and 4h. The results show that heat treatment resulted in a darkened color, decreased moisture performance and increased dimensional stability of wood. Compared with untreated wood, equilibrium moisture content (EMC), water absorption (WA) and volume swelling (VS) for treated wood decrease up to 42.63%, 34.93% and 67.47%. The higher the treatment temperature and the longer the treatment time, the lower EMC, WA and VS. The VS of treated specimens has a more significant reduction than EMC and WA when the heat treatment temperature is above 180°C. The visual color changes were more distinct after heat treatment above 180°C. Temperature has a greater influence than time on these properties of specimens.