Balloon pre-dilation is usually performed before implantation of a nitinol stent in a femoropopliteal artery in a case of severe blockage or calcified plaque. However, its effect on performance of the nitinol stent in a diseased femoropopliteal artery has not been studied yet. This study compares the outcomes of stenting with pre-dilation and without it by modelling the entire processes of stent deployment. Fatigue deformation of the implanted stent is also modelled under diastolic–systolic blood pressure, repetitive bending, torsion, axial compression and their combination. Reduced level of stress in the stent occurs after stenting with pre-dilation, but causing the increased damage in the media layer, i.e. the middle layer of the arterial wall. Generally, pre-dilation increases the risk of nitinol stent’s fatigue failure. Additionally, the development of in-stent restenosis is predicted based on the stenting-induced tissue damage in the media layer, and no severe mechanical irritation is induced to the media layer by pre-dilation, stent deployment or fatigue loading.
Antonie van Leeuwenhoek - Tremella fuciformis is a dimorphic fungus which can undertake the reversible transition between yeast and pseudohypha forms. G protein α subunit (Gα) carries... 相似文献
Lipases are widely used for a variety of biotechnological applications. Screening these industrial enzymes directly from environmental microorganisms is a more efficient and practical approach than conventional cultivation-dependent methods. Combined with activity-based functional screening, six clones with lipase activity were detected and a gene (termed lipZ01) isolated from a target clone with the highest lipase activity was cloned from an oil-contaminated soil-derived metagenomic library and then sequenced. Gene lipZ01 was expressed in Pichia pastoris GS115 and the molecular weight of the recombinant lipase LipZ01 was estimated by electrophoresis analysis to be approximately 50 kDa. The maximum activity of the purified lipase was 42 U/mL, and the optimum reaction temperature and pH value were 45 °C and 8.0, respectively. The enzyme was highly stable in the temperature range 35–60 °C and under alkaline conditions (pH 7–10). The presence of Ca2+ and Mn2+ ions could significantly enhance the activity of the lipase. The purified lipase preferentially hydrolysed triacylglycerols with acyl chain lengths ≥8 carbon atoms, and the conversion degree of biodiesel production was nearly 92% in a transesterification reaction using olive oil and methanol. Some attractive properties suggested that the recombinant lipase may be valuable in industrial applications. 相似文献
Mycelia of a wild strain Poria cocos were cultured in two media differing in one constituent: bran extract or corn steep liquor, and are designated as wb and wc, respectively. Six polysaccharide fractions were isolated sequentially from the two mycelia by 0.9% NaCl (PCM1), hot water (PCM2), 0.5 M NaOH (PCM3-I and -II) and 88% formic acid (PCM4-I and -II). Their chemical and physical characteristics were determined by infrared spectroscopy (IR), gas chromatography (GC), 13C NMR, light scattering (LS) and viscometry. The results indicated that wb-, wc-PCM1, and PCM2 were heteropolysaccharides mainly composed of alpha-D-glucose, mannose, and galactose, whereas wb-PCM3-I and wc-PCM3-I were mainly (1-->3)-alpha-D-glucans, and wb- and wc-PCM3-II, PCM4-I and PCM4-II were (1-->3)-beta-D-glucans. Interestingly, (1-->3) alpha- and (1-->3)-beta-D-glucans co-existed in the 0.5 M NaOH fraction and were separated individually into the two fractions (PCM3-I and PCM3-II) after neutralizing with acetic acid. The polysaccharides from wc-PCM cultured in media containing corn steep liquor contained relatively more protein. The polysaccharide fractions also existed in conformations including random coil (as in PCM0 and PCM1) and expanded chain (as in PCM3), and differed molecular mass. In addition, two exo-polysaccharides isolated from the two culture media by methanol precipitation (wb- and wc-PCM0) also differed in their monosaccharide composition. 相似文献
Death receptor 6 (DR6) is a member of the death domain-containing receptors that belong to the TNFR superfamily. To date, the ligand for DR6 is still not clearly defined. Here, we developed a functional agonist monoclonal antibody (DQM3) against DR6, which bound to the first cysteine-rich domain. Importantly, DR6 signaling could be clearly activated by DQM3, which was dependent on its intracellular death domain. In addition, we demonstrated that the association between DR6 and TRADD was enhanced upon DQM3 stimulation and TRADD was involved in DR6-induced signaling activation. Taken together, our findings provide new insight into a novel mechanism by which DR6 induces downstream signaling in response to an agonist antibody. 相似文献