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In this study, strontium substituted hydroxyapatite (Sr-HAP) was synthesized using collagen type I and citrate as bi-templates and the obtained nanoparticles with high similarity to natural bone minerals were made into composite scaffolds with interconnected porous structure using a three-dimensional (3D) printing technique. A calcium deficient structure of HAP phase was caused by doping Sr which was verified by Fourier transform infrared, x-ray diffractometer, scanning electron microscopy and transmission electron microscopy. The Sr/(Sr + Ca) molar ratio in Sr-HAP nanoparticles was 5.8% estimated by EDX. Furthermore, both 3D printed scaffolds made of Sr-HAP and HAP had uniform porous structure and porosity of about 60%. Cell culturing indicated that MC3T3-E1 cells could adhere on the surface of the scaffolds and the strontium substitution could enhance cell adhesion, proliferation and alkaline phosphatase activity. The printed composite scaffolds were used to repair critical-sized rabbit calvarial defects with a diameter of 15 mm. The results showed that the Sr-HAP scaffolds had better osteogenic capability and stimulated more new bone formation within 12 weeks. It was suggested that these printed Sr-HAP composite scaffolds possessed high potential as candidates in the application of bone augmentation and regeneration.

Microparticles (MPs) are associated with several cardiovas-cular complications. As multifunction biomarkers, they may contribute to the pathogenesis of diabetes-associated vas-cular diseases. A total of 39 patients with diabetes and hypertension, 24 patients with diabetes without hyper-tension, and 20 healthy controls were enrolled. Flow cytometry was applied to detect plasma MPs, including endothelial MPs (EMPs), annexin V+MPs, platelet-derived MPs (PMPs), and leukocyte-derived MPs (LMPs). Brachial ankle pulse wave velocity (baPWV) was also performed in admission. Plasma EMPs, annexin V+MPs, PMPs, and LMPs in diabetics with or without hypertension were higher than those in control patients. Among diabetics, only EMPs in patients with hypertension was higher than in those without hypertension. Correlation analysis showed that systolic blood pressure and mean blood pressure were positively correlated with EMPs. Multivariant analysis demonstrated that EMP was an independent risk factor for the presence of hypertension in diabetics (odds ratio, 2.822; 95% confidence interval, 1.265-6.296; P=.011). Furthermore, baPWV in diabetics with hypertension (1910AE355 cm ⁄ s) was higher than that in control patients (1441AE198 cm ⁄ s) and diabetics without hypertension (1727AE2 cm ⁄ s). Multivariant analysis identified EMP as a potent contributor to the development of impaired artery elasticity in diabetics (odds ratio, 4.401; 95% confidence interval, 1.529-12.673; P=.006). Plasma EMP was associated with the presence of hypertension and impaired arterial stiffness in type 2 diabetes. J Clin Hypertens (Greenwich). 2012; 14:455-460. Ó2012 Wiley Periodicals, Inc.

Instruments used in endoscopic surgery (colonoscopy surgery or natural orifice transluminal endoscopic surgery (NOTES)) are flexible to be advanced in human body. However, when the end of the instrument reaches the target, the instrument should be rigid enough to hold its shape against external forces for better surgical accuracy. In order to obtain these two properties, a variable stiffness over tube based on low-melting-point-alloy (LMPA) is proposed in this paper. The structure exploits the phase transformation property of the LMPA which enables the stiffness change of the over tube by heating and cooling. A prototype was fabricated using a special molding method, and experiments were carried out to evaluate its variable stiffness property and response characteristics. According to experimental results, it costs 17 s to make the over tube transform from rigid state to flexible state and 18 s to make the over tube transform from flexible state to rigid state. The experimental results also indicated that the over tube is very rigid in rigid state and flexible in compliant state. A heat insulation layer was assembled to prevent human tissue from thermal damage. The temperature of the outer wall of the over tube was 42.5 °C when hot water of 80 °C was pumped into the over tube continually with the help of the heat insulation layer.

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