Objective
Microvascular malperfusion after myocardial infarction leads to infarct expansion, adverse remodeling, and functional impairment. Native reparative mechanisms exist but are inadequate to vascularize ischemic myocardium. We hypothesized that a 3-dimensional human fibroblast culture (3DFC) functions as a sustained source of angiogenic cytokines, thereby augmenting native angiogenesis and limiting adverse effects of myocardial ischemia.
Methods
Lewis rats underwent ligation of the left anterior descending coronary artery to induce heart failure; experimental animals received a 3DFC scaffold to the ischemic region. Border-zone tissue was analyzed for the presence of human fibroblast surface protein, vascular endothelial growth factor, and hepatocyte growth factor. Cardiac function was assessed with echocardiography and pressure–volume conductance. Hearts underwent immunohistochemical analysis of angiogenesis by co-localization of platelet endothelial cell adhesion molecule and alpha smooth muscle actin and by digital analysis of ventricular geometry. Microvascular angiography was performed with fluorescein-labeled lectin to assess perfusion.
Results
Immunoblotting confirmed the presence of human fibroblast surface protein in rats receiving 3DFC, indicating survival of transplanted cells. Increased expression of vascular endothelial growth factor and hepatocyte growth factor in experimental rats confirmed elution by the 3DFC. Microvasculature expressing platelet endothelial cell adhesion molecule/alpha smooth muscle actin was increased in infarct and border-zone regions of rats receiving 3DFC. Microvascular perfusion was also improved in infarct and border-zone regions in these rats. Rats receiving 3DFC had increased wall thickness, smaller infarct area, and smaller infarct fraction. Echocardiography and pressure–volume measurements showed that cardiac function was preserved in these rats.
Conclusions
Application of a bioengineered 3DFC augments native angiogenesis through delivery of angiogenic cytokines to ischemic myocardium. This yields improved microvascular perfusion, limits infarct progression and adverse remodeling, and improves ventricular function.
This paper discusses aspects of long distance, large capacity, and high speed belt conveyor design. The study is focused mainly on the whole arrangement and main components configuration of Belt Conveyor, including driving device, conveyor belt, drum and rollers etc. With increasing demand for the long distance, large capacity belt conveyors, its designing and manufacturing level will be improved.
In the essay, the Low carbon ductile iron by laser surface alloying processing has been experimentally studied. Results indicate that on low carbon ductile iron matrix coated with different alloy powder, structure of laser surface alloying processing is very small, the combination quality between alloying layer and matrix is good. Low carbon ductile iron after laser surface treatment, maternal surface hardness are greatly enhanced, maternal surface hardness increasing from HV250~330 to the highest about HV1400, surface laser hardening effect of Low carbon ductile iron is very obvious.
Viscous pressure forming (VPF) is a new developed sheet soft-punch forming process in 1900s. The basic principle and characteristics of VPF are described. The applications of VPF technologies of nickel-based super-alloy corrugated thin-walled part, asymmetrical thin-wall part with variable diameter, super-alloy thin-walled part with variable diameters, corrugated thin-walled part with larger diameter and small section are presented. The results show that VPF is suitable for the forming of parts with high strength, low plasticity, super thin-wall and complex shaped.
The novel modified vermiculite adsorbents have been made impregnated with sulfate, HCl and CuCl2. A laboratory-scale packed-bed reactor system was used to screen these adsorbents for their capability to remove elemental mercury. The affection of temperature on adsorption was also detected. Results showed that the adsorption capability for elemental mercury was improved after treated by different modified agents than the natural vermiculite. Comparing with active carbon, the adsorption capability of vermiculite adsorbents modified by sulfate and HCl were less improved, and it is almost increased 40 times than that of active carbon when using the CuCl2modified vermiculite adsorbent at the same condition. Increasing temperature is active for the adsorption capability for elemental mercury by sulfate and HCl modified vermiculite adsorbents.
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