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11.
The mechanism responsible for the thrombotic complications of atherosclerotic plaques is not well understood. Although a role for tissue factor (TF) has been hypothesized, there are scant data on the presence, location, quantity, and activity of TF in atherosclerotic plaques. The purpose of this study was to show the localization of TF in human atherosclerotic plaques. Digoxigenin-labeled factors VIIa and X were used to demonstrate their specific binding sites in formalin-fixed, paraffin-embedded human arteries by incubation of sections with the labeled factor and localization of TF:factor(s) complexes by immunohistochemical staining for digoxigenin. In sections of atherosclerotic plaques, diffuse staining was most intense in the relatively acellular, lipid-rich core but was also present intracellularly in macrophages and smooth muscle cells and, to a lesser extent, in the relatively acellular fibrous tissue of the plaque. Endothelial cells overlying plaques and occasional medial smooth muscle cells stained positively as well. The adventitia routinely stained for TF in both normal and diseased artery segments. Staining for labeled factor VIIa was blocked when sections were preincubated with a 10-fold excess of unlabeled factor VIIa or with a polyclonal antihuman TF antibody. Binding of labeled factors VIIa and X was Ca(2+)-dependent. In conclusion, binding of digoxigenin-labeled factors VIIa and X shows that the lipid rich core of atherosclerotic plaques contains high levels of extracellular TF. This location may be responsible for the rapid initiation of thrombosis when lipid rich atherosclerotic plaques rupture and the core contents are exposed to flowing blood.  相似文献   
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13.
Quantum cascade lasers have ushered in a new era of enhanced capability for chemical sensing. The higher current and voltage demands of these devices over their laser diode counterparts have also ushered in the demand for more capable drive electronics. The current-sensitivity and high frequency response of these devices have continued the desire for low noise, stability, and agility enjoyed by the laser diode community for many years. This article addresses the issue of maintaining these characteristics at the currents and voltages required, and presents example performance of current controllers developed by the author at Pacific Northwest National Laboratory, achieving output currents up to 2 A and compliance voltages of 15 V, with noise levels close to the Johnson noise of the internal resistors, typically a few nA/√Hz. Rapid full-depth current modulation up to 100 kHz is also demonstrated.  相似文献   
14.
Young drivers in Israel, as in other parts of the world, are involved in car crashes more than any other age group. The graduated driver licensing system in Israel requires that all new drivers be accompanied by an experienced driver whenever they drive for the first 3 months after obtaining a driving license. In an effort to make the accompanied driving phase more effective, a novel program which targets both young drivers and their parents was initiated in 2005. The program administers a personal meeting with the young driver and the accompanying parent scheduled for the beginning of the accompanied driving phase. In this meeting guidance is given regarding best practices for undertaking the accompanied driving, as well as tips for dealing with in-vehicle parent–teen dynamics. Through 2008, almost 130,000 families of young drivers have participated in the program.  相似文献   
15.
The associations between driving styles and the Big-Five personality factors and perceived costs and benefits of driving were examined in order to obtain a more comprehensive understanding of driving styles. Questionnaires tapping driving style, personality traits, motivations for driving, and background variables were completed by 320 drivers (150 men and 170 women). The results show that each driving style is associated with a unique set of sociodemographic, personality, and motivational factors. The reckless and angry styles were both endorsed more by men than women, by younger drivers, and by those displaying higher levels of Extroversion and thrill seeking, and lower levels of Agreeableness and Conscientiousness. However, whereas the reckless style was also predicted by the perceived costs of driving-related distress, as well as higher perceived risk to life among those with higher education, the angry style was also predicted by perceptions of both control and annoyance among more educated drivers. The anxious style was endorsed more by women, and by drivers lower on Conscientiousness and higher on Neuroticism. Individuals reporting this style regard driving as a cause of distress and annoyance, and, depending on their level of education, perceive it as entailing more risk to life and as a potential damage to their self-image (higher education), or as providing more opportunities for impression management (lower education). The careful driving style was endorsed more by women, and associated with higher Agreeableness, Conscientiousness, and Openness, along with higher pleasure (especially among younger drivers), but lower thrill seeking and worries about damage to self-esteem. The discussion focuses on the importance of looking at driving styles and their predictors holistically in order to design practical interventions suited to different profiles of drivers.  相似文献   
16.
The current study examined the applicability of the Family Climate for Road Safety Scale (FCRSS; Taubman-Ben-Ari and Katz-Ben-Ami, 2013) to the parents of young drivers. The sample consisted of 549 parents and 234 of their children, all of whom completed the FCRSS. In addition, the parents completed the multidimensional driving style inventory (MDSI; Taubman-Ben-Ari et al., 2004) and provided background data (e.g., age, gender). Confirmatory factor analysis supported a slightly modified structure of the scale for parents. Examination of the correlations revealed significant weak to strong associations between parents’ scores on the various FCRSS dimensions on the one hand, and their self-reported driving styles and offspring’s perceptions of the family climate for safety on the other. The findings indicate that the FCRSS is suitable for use with the parents of young drivers, and that perceptions of the family climate are shared by the two generations. Furthermore, they show that family climate is related to parents’ customary driving behavior, with the careful driving style positively related to the positive dimensions of the FCRSS. The discussion stresses the importance of the parents’ influence on the manner in which their children drive, and the multifaceted nature of this influence. Moreover, it indicates the potential value of the FCRSS, both for research and for designing interventions and measuring their effectiveness.  相似文献   
17.
Orientation adaptive subband coding of images   总被引:1,自引:0,他引:1  
In the subband coding of images, directionality of image features has thus far been exploited very little. The proposed subband coding scheme utilizes orientation of local image features to avoid the highly objectionable Gibbs-like phenomena observed at reconstructed image edges with conventional subband schemes at low bit rates, At comparable bit rates, the subjective image quality obtained by our orientation adaptive scheme is considerably enhanced over a conventional separable subband coding scheme, as well as other separable approaches such as the JPEG compression standard.  相似文献   
18.
We propose a new framework for highly scalable video compression, using a lifting-based invertible motion adaptive transform (LIMAT). We use motion-compensated lifting steps to implement the temporal wavelet transform, which preserves invertibility, regardless of the motion model. By contrast, the invertibility requirement has restricted previous approaches to either block-based or global motion compensation. We show that the proposed framework effectively applies the temporal wavelet transform along a set of motion trajectories. An implementation demonstrates high coding gain from a finely embedded, scalable compressed bit-stream. Results also demonstrate the effectiveness of temporal wavelet kernels other than the simple Haar, and the benefits of complex motion modeling, using a deformable triangular mesh. These advances are either incompatible or difficult to achieve with previously proposed strategies for scalable video compression. Video sequences reconstructed at reduced frame-rates, from subsets of the compressed bit-stream, demonstrate the visually pleasing properties expected from low-pass filtering along the motion trajectories. The paper also describes a compact representation for the motion parameters, having motion overhead comparable to that of motion-compensated predictive coders. Our experimental results compare favorably to others reported in the literature, however, our principal objective is to motivate a new framework for highly scalable video compression.  相似文献   
19.
BACKGROUND: Elevated levels of lipoprotein(a) [Lp(a)] are associated with premature atherosclerosis; however, the mechanisms are not known. Recruitment of monocytes to the blood vessel wall is an early event in atherogenesis. METHODS AND RESULTS: This study has found that unoxidized Lp(a) induced human umbilical vein endothelial cells (HUVECs) to secrete monocyte chemotactic activity (MCA), whereas LDL under the same conditions did not. In the absence of HUVECs, Lp(a) had no direct MCA. Endotoxin was shown not to be responsible for the induction of MCA. Actinomycin D and cycloheximide inhibited the HUVEC response to Lp(a), indicating that protein and RNA synthesis were required. The apolipoprotein(a) [apo(a)] portion of Lp(a) was identified as the structural component of Lp(a) responsible for inducing MCA. Lp(a) and apo(a) also stimulated human coronary artery endothelial cells to produce MCA. Granulocyte-monocyte colony-stimulating factor (GM-CSF) antigen was not detected in the Lp(a)-conditioned medium, nor was monocyte chemoattractant protein-1 mRNA induced in HUVECs by Lp(a). CONCLUSIONS: These findings suggest that Lp(a) may be involved in the recruitment of monocytes to the vessel wall and provide a novel mechanism for the participation of Lp(a) in the atherogenic process.  相似文献   
20.
A child had malignant pheochromocytoma. Her tumor originally was thought to be a benign one, but persistent elevation of catecholamine values in the post operative period, and consequent appearance of lytic bone lesions, proved her disease to be metastatic. Malignancy is rare in this tumor, and difficult to diagnose even with sophisticated biochemical radiologic techniques. Treatment with chemotherapy and radiation failed to halt the spread and growth of this patient's tumor.  相似文献   
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