The through-plane permeability of the gas diffusion media (GDM) is investigated experimentally with regard to microporous layer (MPL) composition and (GDL) structure. MPL held constant at 80% carbon powder 20% polytetrafluorethylene (PTFE) (by weight) for various loadings. decrease or increase in GDM was found be dependent on structure GDL used conjunction type powder. It that low-surface-area ...

Attachment of 111Indium-oxine labeled cultured canine venous endothelial cells to expanded polytetrafluorethylene (ePTFE) grafts was evaluated in vitro. Three alternative seeding techniques were studied in grafts having different diameters, porosities, and surfaces, including: (I) manual milking of blood containing endothelial cells within the graft; (II) a two-step procedure of incubating graf...

The aim of this study was to evaluate the color stability of composites subjected to different periods of accelerated artificial aging (AAA). A polytetrafluorethylene matrix (10 x 2 mm) was used to fabricate 24 test specimens of three different composites (n=8): Tetric Ceram (Ivoclar/Vivadent); Filtek P90 and Z250 (3M ESPE), shade A3. After light activation for 20 s (FlashLite 1401), polishing ...

Aim. To compare the differences between medial and intercondylar infragenicular femoropopliteal prosthetic bypasses in terms of their midterm patency and limb salvage rates. Methods. Ninety-three consecutive patients with peripheral arterial disease who underwent a simple distal femoropopliteal bypass using a reinforced polytetrafluorethylene graft were included in this retrospective study. The...

Poly(glycerol-sebacate) (PGS) is an elastomeric biodegradable polyester that could potentially be used to engineer blood vessels in vivo. However, its blood-material interactions are unknown. The objectives of this study were to: (a) fabricate PGS-based biphasic tubular scaffolds and (b) assess the blood compatibility of PGS in vitro in order to get some insight into its potential use in vivo. ...

BACKGROUND Dialysis vascular access complications are considered as significant causes of morbidity in chronic hemodialysis patients. OBJECTIVES The aim of the present study was a comparison of axillary loop and straight grafts patency and its complications in hemodialysis access. PATIENTS AND METHODS In this cohort study conducted at Shahid Beheshti Medical University, 77 patients who unde...

Intimal hyperplasia (IH), which causes occlusion of arterial bypass grafts and arteriovenous (A-V) shunts, develops preferentially in low wall shear, or stagnation, regions. Arterial geometry is commonly three-dimensional, generating swirling flows, the characteristics of which include in-plane mixing and inhibition of stagnation. Clinical arterial bypass grafts are commonly two-dimensional, fa...

The combination of hydrophobic membranes and microbial electrolysis cells (MEC) was assessed in two different configurations order to recover ammonia from anaerobically digested pig slurry. Polytetrafluorethylene (PTFE) were inserted both an H-type three-chamber cell (MEC-H) a two-chamber sandwich configuration MEC (MEC-S), fitted with cationic exchange membrane (CEM) dividing the anode cathode...

The current study investigates experimentally the potential of integrating a scroll expander into a micro cogeneration steam Rankine cycle. This expander technology is not an existing technical option for such applications; consequently an existing oil-free scroll compressor is adapted to run in an expander mode with water as working fluid. The performance of the adapted scroll expander, with d...

After myocardial infarction, the implantation of stem cell seeded scaffolds on the ischemic zone represents a promising strategy for restoration of heart function. However, mechanical integrity and functionality of tissue engineered constructs need to be determined prior to implantation. Therefore, in this study a novel pulsatile bioreactor mimicking the myocardial contraction was developed to ...