Prolonged Growth Time Research Articles

Corn trypsin inhibitor decreases tissue-type plasminogen activator-mediated fibrinolysis of human plasma

Corn trypsin inhibitor (CTI) has been considered the molecule of choice to inhibit activated factor XII (FXIIa) during the conduct of experimentation focusing on tissue factor-initiated coagulation. However, CTI-mediated attenuation of fibrinolysis following celite activation of coagulation was observed in pilot studies with the clot lifespan model. The goal of the present study was thus to characterize the mechanism(s) responsible for CTI-mediated hypofibrinolysis. Normal plasma was exposed to 0 or 49.6 microg/ml CTI, with coagulation initiated with celite or tissue factor. Fibrinolysis was initiated with tissue-type plasminogen activator (tPA). Additional experiments utilized plasminogen activator inhibitor 1 deficient or alpha2-antiplasmin-deficient plasma. Coagulation/fibrinolysis kinetics were monitored with the thrombelastography-based clot lifespan model. In addition to delaying the initiation of coagulation, CTI prolonged clot growth time, delayed the onset of lysis, and prolonged clot lysis time in normal plasma after celite activation. Conversely, CTI increased the speed of clot growth, clot strength, and prolonged clot lysis time after tissue factor activation. Experiments with plasma deficient in antifibrinolytic proteins supported a primary inhibition of tPA by CTI. In addition to anti-FXIIa effects following celite activation, CTI likely exerts an anti-tPA effect, which contributed to hypofibrinolysis in this model.

Growth and photoluminescence characteristics of ZnO tripods

Hexagonal and preferentially oriented three-dimensional ZnO tripods have been grown on p-Si [100] substrates by a simple vapor-solid technique without using any catalysts. The tripodal-core growth route involves the formation of a hexagonal disk with [0002] larger surfaces. The tripods show irreversible shape transformation to tetrapods at higher temperature and prolonged growth time. Temperature-dependent photoluminescence characteristics of ZnO tripods have been investigated in the range from 10 to 300 K. Multiple LO phonon-assisted emissions associated with both bound and free excitons are observed for tripods, the origin of which have been explained by Permogorov’s theory for II–VI semiconductors.

Impact of adjuvant inhibition of vascular endothelial growth factor receptor tyrosine kinases on tumor growth delay and local tumor control after fractionated irradiation in human squamous cell carcinomas in nude mice

Previous experiments have shown that adjuvant inhibition of the vascular endothelial growth factor receptor after fractionated irradiation prolonged tumor growth delay and may also improve local tumor control. To test the latter hypothesis, local tumor control experiments were performed. Human FaDu and UT-SCC-14 squamous cell carcinomas were studied in nude mice. The vascular endothelial growth factor receptor tyrosine kinase inhibitor PTK787/ZK222584 (50 mg/kg body weight b.i.d.) was administered for 75 days after irradiation with 30 fractions within 6 weeks. Tumor growth time and tumor control dose 50% (TCD(50)) were determined and compared to controls (carrier without PTK787/ZK222584). Adjuvant administration of PTK787/ZK222584 significantly prolonged tumor growth time to reach 5 times the volume at start of drug treatment by an average of 11 days (95% confidence interval 0.06;22) in FaDu tumors and 29 days (0.6;58) in UT-SCC-14 tumors. In both tumor models, TCD(50) values were not statistically significantly different between the groups treated with PTK787/ZK222584 compared to controls. Long-term inhibition of angiogenesis after radiotherapy significantly reduced the growth rate of local recurrences but did not improve local tumor control. This indicates that recurrences after irradiation depend on vascular endothelial growth factor-driven angiogenesis, but surviving tumor cells retain their clonogenic potential during adjuvant antiangiogenic treatment with PTK787/ZK222584.

Epitaxial Growth of InN by Halogen Transport Method

InN was epitaxially grown on (0001) α-Al2O3 substrates by the halogen transport method. Surface treatment of the substrate by a H2+Br2 gas (passed over In) just before the growth was essential for obtaining the epitaxial layers of InN. Arrays of extra spots were observed in the reflection electron-diffraction patterns of thin InN films. The extra spot arrays could be explained from the viewpoint that the crystal film was composed of twins. In these twin structures, the twinning planes were (7̄ 12 5̄ 0) and (1̄ 1̄ 20 9̄ 0). These extra spots ultimately disappeared with prolonged growth time. This result shows that as the growth proceeds, crystallites having a predominant orientation overwhelm other crystallites.