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Carotid atherosclerosis one of the main risk factors for ischemic stroke. Acute thrombosis after atherosclerotic plaque disruption is a major complication of primary atherosclerosis, leading to acute ischemic syndromes and atherosclerotic progression. PAI-1 is the most important and most rapidly acting physiological inhibitor of tissue-type (t-PA) and urokinase type (u-PA) plasminogen activators. Active PAI-1 form spontaneously converts to the latent with a half-life of ~1 h. Complex formation with vitronectin increases half life of PAI-1 by two- to four-folds. Thus, this inhibitor function of PAI-1 facilitated by Vn that binds the inhibitor and may regulate its activity by the stabilizing the active PAI-1 conformation. In addition, PAI-1/VN complexes may effect vascular structure and function. However, the exact role of these complexes in vascular remodelling are not completely clear. The aim of the present study was determining, correlating and comparing the plasma vitronectin, t-PA and PAI-1 activity levels in asymptomatic and symptomatic patients with carotid artery plaque.A total of 37 carotid artery disease patients were included in this study. Blood samples were obtained from Cerrahpasa Medical School, Department of Heart and Vessel Surgery, University of Istanbul. Plasma vitronectin, tPA and PAI-1 activity levels were determined by ELISA.We found plasma PAI-1 activity levels were elevated in the asymptomatic group as compared with symptomatic group (P=0.038). We have also found a positive correlation between PAI-1 activity and vitronectin levels in symptomatic group (r=0.399, P=0.039).Decreased PAI-1 activity levels correlate with vitronectin in the symptomatic group; a) may be the consequence a compensatory mechanisms (due to possibilty in increased fibrinolytic activity and decreased vascular remodelling) against disease progression. b) or may be also cause progression of disease by increase of vascular remodelling.

The ePix detector family provides multiple variants of hybrid pixel detectors to support a wide range of applications at free electron laser facilities. We present the results of a systematic study of the influence of radiation induced damage on the performance and lifetime of an ePix100a detector module using a direct attenuated beam of the EuXFEL at 9 keV photon energy and an average power of 10 $\mu$W. An area of 20 x 20 pixels was irradiated with an average photon flux of approx. 7 x $10^{9}$ photons/s to a dose of approximately 760$\pm$65 kGy at the location of the Si/SiO$_2$ interfaces in the sensor. A dose dependent increase in both offset and noise of the ePix100a detector have been observed originating from an increase of the sensor leakage current. Moreover, we observed an effect directly after irradiation resulting in the saturation of individual pixels by their dark current. Changes in gain are evaluated one and half hours post irradiation and suggest damage to occur also on the ASIC level. Based on the obtained results, thresholds for beam parameters are deduced and the detector lifetime is estimated with respect to the requirements to the data quality in order to satisfy the scientific standards defined by the experiments. We conclude the detector can withstand a beam with an energy up to 1 $\mu$J at a photon energy of 9 keV impacting on an area of 1 mm$^2$. The detector can be used without significant degradation of its performance for several years if the incident photon beam intensities do not exceed the detector's dynamic range by at least three orders of magnitude. Our results provide valuable input for the operation of the ePix100a detector at FEL facilities and for the design of future detector technology., Comment: 25 pages, 15 figures, accepted for publication by the Journal of Instrumentation