RESUMEN
Fog-collecting meshes show a great potential in ensuring the availability of a supply of sustainable freshwater in certain arid regions. In most cases, the meshes are made of hydrophilic smooth fibers. Based on the study of plant surfaces, we analyzed the fog collection using various polyethylene terephthalate (PET) fibers with different cross sections and surface structures with the aim of developing optimized biomimetic fog collectors. Water droplet movement and the onset of dripping from fiber samples were compared. Fibers with round, oval, and rectangular cross sections with round edges showed higher fog-collection performance than those with other cross sections. However, other parameters, for example, width, surface structure, wettability, and so forth, also influenced the performance. The directional delivery of the collected fog droplets by wavy/v-shaped microgrooves on the surface of the fibers enhances the formation of a water film and their fog collection. A numerical simulation of the water droplet spreading behavior strongly supports these findings. Therefore, our study suggests the use of fibers with a round cross section, a microgrooved surface, and an optimized width for an efficient fog collection.
RESUMEN
OBJECTIVE: Stent implantation into atherosclerotic coronary vessels induces the release of particulate debris and soluble vasoactive substances, which impair downstream microvascular function. Microvascular perfusion, however, is also determined by hemorheological parameters. We therefore analyzed now changes in erythrocyte (RBC) aggregation in coronary arterial blood during stent implantation. METHODS: Symptomatic male patients with stable angina pectoris and stenosis in their native right coronary artery (RCA) or saphenous vein graft on right coronary artery (SVG-RCA) were enrolled. Coronary arterial blood was taken before and coronary aspirate during stent implantation with a distal occlusion/aspiration device. RBC aggregation was determined using the erythrocyte adhesiveness/aggregation test. The ratio of clot-free area to whole area of a spread blood drop was quantified (rCFA). To evaluate the impact of soluble factors within aspirate plasma on RBC aggregation, separated RBCs of healthy volunteers were exposed to patients' coronary arterial blood and aspirate samples. RESULTS: rCFA was comparably increased in coronary aspirate of RCAs and SVG-RCAs after stent implantation (RCA: 25.7±2.1% vs 32.2±2.1%; SVG-RCA: 28.9±1.9% vs 33.3±2.0%, P<.01). The rCFA of healthy volunteers was increased after adding coronary aspirate plasma. CONCLUSIONS: Stent implantation into atherosclerotic coronary arteries induces an increase in RBC aggregation, potentially contributing to impaired microvascular perfusion.