BACKGROUND: Thrombus formation and neointimal hyperplasia limit its use for revascularization of small-caliber vessels (<6mm diameter) in the coronary or peripheral circulation.OBJECTIVE: To improve hemocompatibility, the luminal surface of a small diameter expanded polytetrafluoroethylene (Eptfe) vascular prosthesis was modified with alginate and recombinant hirudin.DESIGN: Observational experiment.SETTING: This study was performed in Nanomedicine and Biosensor Laboratory, Bio-X Center, Harbin Institute of Technology from Marcy 2006 to June 2007.MATERIALS: The GORE-TEX Epife vascular grafts (W. L Gore & Associates, Inc., Flagstaff, AZ) used in this study were 4mm in internal diameter. rHir was obtained from Calbiochem, Germany. Sodium alginate (also called alginic acid sodium salt; medium viscosity) was purchased from Sigma.METHODS: A p-diazonium diphenyl amine polymer (PA) was used as an interlayer between alginate and recombinant hirudin (rHir). The diazonium moieties were capable of covalently coupling with electron-rich aromatic systems such as histidine and tyrosine residues of hirudin. No need for chemical pretreatment took all advantage by preserving the bulk properties with almost no effect on stability and elasticity of the Eptfe vascular graft. rHir amount on Epife surface Was determined by the Micro BCA (Bicinchoninic acid) Protein Assay kit.MAIN OUTCOME MEASURES: ① Determination rHir amount on Eptfe surface; ② Static water contact angles; ③ Attenuated total reflectance fourier transform infrared spectroscopy (ATR-FTIR) was employed to confirm the change taking place in the Eptfe graft surface modification process; ④ Characterization of the surface morphology and platelet adhesion by SEM; ⑤ APTT and PT; ⑥ Percent hemolysis.RESULTS: ① The amount of rHir adsorbed onto the Eptfe vascular was deduced to be 16.35 μg/cm2. ② Surface analysis ATR-FTTR revealed the presence of new functional groups on the modified graft surfaces. ③ The water contact angle of the modified graft surface decreased. ④ The longer APTT and PT value lower than 5% hemolysis level and dramatically decrease of platelet adhesion assay showed that rHir modified graft had great improved blood compatibility.CONCLUS10N: Cross-linked Alg/rHir onto Eptfe can improve luminal surface and hemocompatibility.

We studied the effect of initial pH and substrate concentrations on the conversion of xylose to hydrogen by Clostridium butyrium T4 at pH 5.0-8.5 and substrate concentrations 5-40 g/L. The cumulative hydrogen volume and the specific hydrogen production rate increased and then decreased with increasing initial pH or substrate concentrations. At initial pH 6.5 and substrate concentration 20 g/L, the cumulative hydrogen production and the specific hydrogen production rate reached the maximum value of 4.26 L/L and 18.86 mmol-H2/h g-DCW (dry cell weight).
Clostridium butyricum ; growth & development ; metabolism ; Culture Media ; Fermentation ; Hydrogen ; analysis ; metabolism ; Hydrogen-Ion Concentration ; Substrate Specificity ; Xylose ; metabolism

Hydrogen production from lignocellulosic biomass is both sustainable and environmentally friendly, which is garnering more and more attention across the world, with an expectation to challenge the shortage of fossil fuels supply and climate change as well. In this article, the update research progress and technology development of biohydrogen production are reviewed, with a focus on biomass pretreatment, hydrogen-producing microorganisms and process engineering strategies. And in the meantime, a roadmap for more efficient and economic biohydrogen production is envisioned.
Bacteria ; metabolism ; Bioelectric Energy Sources ; microbiology ; trends ; Biomass ; Biotransformation ; Fermentation ; Hydrogen ; metabolism ; Lignin ; metabolism