Dystrophin Deficiency Causes Progressive Depletion of Cardiovascular Progenitor Cells in the Heart

Duchenne muscular dystrophy (DMD) is a devastating condition shortening the lifespan of young men. DMD patients suffer from age-related dilated cardiomyopathy (DCM) that leads to heart failure. Several molecular mechanisms leading to cardiomyocyte death in DMD have been described. However, the pathological progression of DMD-associated DCM remains unclear. In skeletal muscle, a dramatic decrease in stem cells, so-called satellite cells, has been shown in DMD patients. Whether similar dysfunction occurs with cardiac muscle cardiovascular progenitor cells (CVPCs) in DMD remains to be explored. We hypothesized that the number of CVPCs decreases in the dystrophin-deficient heart with age and disease state, contributing to DCM progression. We used the dystrophin-deficient mouse model (mdx) to investigate age-dependent CVPC properties. Using quantitative PCR, flow cytometry, speckle tracking echocardiography, and immunofluorescence, we revealed that young mdx mice exhibit elevated CVPCs. We observed a rapid age-related CVPC depletion, coinciding with the progressive onset of cardiac dysfunction. Moreover, mdx CVPCs displayed increased DNA damage, suggesting impaired cardiac muscle homeostasis. Overall, our results identify the early recruitment of CVPCs in dystrophic hearts and their fast depletion with ageing. This latter depletion may participate in the fibrosis development and the acceleration onset of the cardiomyopathy.     

互联网零售商

你可能不会在沃尔玛买到一架牛拉风车,但只要这种产品存在,你肯定能在网上找到它     

苹果变芯

苹果公司会宣告它将采用安腾处理器     

Application of fuzzy set theory to industrial pollution prevention: production system modeling and life cycle assessment

 This research describes a framework and case study application that merges fuzzy set methods, pollution prevention, and sustainable production concepts. There is a direct linkage between industrial pollution prevention, sustainability, and the solution of large-scale environmental problems. This linkage stems from the inherent desire for economic production, while at the same time protecting the environment from further degradation. The methodology combines systems analysis under imprecise conditions with a life cycle assessment method that is able to accept imprecise data. Analysis of systems under imprecise conditions is accomplished through analysis of process flow diagrams using fuzzy set techniques. Introduction of imprecision into life cycle assessment is accomplished by integration of fuzzy set approaches into a decision support system utilizing multiple criteria decision making. The framework is described and a case study application of an industrial parts cleaning system using an open top vapor degreaser is presented. Results of applying the method show that: (1) It is well suited for analysis of complex systems in which input data is sparse and expensive to collect. (2) The proposed framework includes a decision support system that is able to consider life cycle assessment concepts, and is able to reconcile differing opinions on available options for modification of production systems, thereby leading to more sustainable solutions. The authors would like to acknowledge the USEPA Region VII Pollution Prevention Division, and the Pollution Prevention Incentives for States program, for their support of this research. In addition, the authors would like to recognize the support of the University of Nebraska Water Resources Center and Center for Infrastructure Research. The authors would also like to thank Dan Crist and Yuezhang Wang for their assistance with fuzzy systems modeling.     

趣闻轶事

名字之谜。我看英特尔又给它的产品想出了一个怪名字，这就是刚宣布的Centrino（中文名“迅驰”），英特尔最新的包括802.11b协议支持的芯片。我猜这是英特尔的一些构词专家们共同琢磨出来的。显然这个名字来自某些词语的组合。诸如中心的（centric），中央的（central），中微子（neutrino）甚至圣婴（bambino）等等。     

Anti-plane Shear Cracks Approaching a Bi-material Interface

A novel procedure is proposed for evaluation of stress intensity factors of planar Mode III shear cracks perpendicular to a nearby interface between two isotropic elastic solids. Shear cracks traversing a flat layer bonded to two different elastic solids are also analyzed. The method is based on superposition of singular near tip stress and displacement fields generated by both the main crack and certain image cracks. Both the main and the image cracks are loaded by self-equilibrating shear tractions of different magnitude, such that matching parts of the said fields are made to satisfy traction and displacement continuity conditions at the interface. Selected comparisons with results obtained by different methods show good agreement. Applications of the method to other crack problems are discussed.     

Stiffness changes in unidirectional composites caused by crack systems

This paper is concerned with the development of constitutive equations for fibrous composites which contain a family of longitudinal slit cracks. The general theory in which the crack length is of the same order as the fiber diameter gives rise to a three-phase model. When the fiber diameter is much smaller than the crack length, we obtain the associated two-phase model. Detailed numerical results are given for selected systems.     

The application of the atomic force microscope to studies of medically important protozoan parasites

Both living and fixed specimens of the medically-important parasitic protozoa, Trypanosoma cruzi, Toxoplasma gondii, Giardia lamblia, Entamoeba histolytica, and Acanthamoeba spp. were studied by atomic force microscopy (AFM). The preparation of fixed specimens was similar to methods used for either scanning or transmission electron microscopy. AFM scanning was performed using both contact and tapping modes. A classical fixation procedure utilizing glutaraldehyde followed by ethanol dehydration was not suitable for all parasite species. AFM images could not be obtained from fixed samples of T. cruzi, T. gondii or E. histolytica. However, excellent topographic images could be obtained from specimens of G. lamblia and Acanthamoeba under identical conditions. Critical point drying permitted AFM imaging of both trypomastigote and epimastigote stages of T. cruzi. Phase imaging of T. cruzi elucidated unique surface details at a level of resolution not visible using any other imaging modalities. AFM elasticity map imaging of T. cruzi-infected and T. gondii-infected cells demonstrated that both parasites were markedly firmer than the surrounding host cell cytoplasm. The parasitophorous vacuole surrounding replicating T. gondii tachyzoites was also visualized by elasticity map imaging. These data suggest that although much remains to be learned about preparing parasitic protozoa for AFM imaging, the technique has the potential of providing unique and important insights into these disease causing organisms.