142 research outputs found

    Identification, regulation and function of a novel lectin-like oxidized low-density lipoprotein receptor

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    AbstractOxidatively modified low-density lipoprotein (ox-LDL) leads to endothelial activation, dysfunction and injury. Recently, a novel lectin-like receptor for ox-LDL (LOX-1) has been identified, primarily in the endothelial cells, and it allows uptake of ox-LDL into endothelial cells. This receptor is transcriptionally upregulated by tumor necrosis factor-alpha, angiotensin II, shear stress and ox-LDL itself. The expression of this receptor activates a variety of intracellular processes that lead to expression of adhesion molecules and endothelial activation. This receptor is highly expressed in the blood vessels of animals and humans with hypertension, diabetes mellitus and atherosclerosis. Expression of this receptor may also be relevant in intra-arterial thrombogenesis and myocardial ischemia-reperfusion injury. Identification and regulation of this receptor and understanding of signal transduction pathways may lead to new therapies of diseases characterized by endothelial dysfunction

    Research on bio-cultural diversity in ethnic areas –based on the investigation of bio-culture in Jinxiu, Guangxi

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    the biological culture as a new cultural concept and form of expression, attaches great importance to the internal relation between culture and biological, enrich and perfect the traditional ecological culture elements such as concept, value orientation, and inspire modest grab in natural resources, respect nature, respect nature of cultural behavior, realize the harmonious development of man and nature. As stewards of local natural ecosystems, ethnic minorities maintain biological diversity through their traditional cultures, such as living customs, religious beliefs and customary laws. As the material basis for its survival, biodiversity also enriches and develops cultural diversity. Biodiversity and cultural diversity interact and develop synergistically. Biological research ethnic areas - the formation and development of cultural diversity, biological and cultural interaction relations, the external factors of biological, cultural diversity and its future development trend of change, the influence of the understanding of the biological culture connotation and biological - synergy to protect cultural diversity has important theoretical and practical significance

    Different Isoforms of Tocopherols Enhance Nitric Oxide Synthase Phosphorylation and Inhibit Human Platelet Aggregation and Lipid Peroxidation: Implications in Therapy with Vitamin E:

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    Background: oc-Tocopherol has received much attention in the primary and secondary prevention of coronary artery disease. Absence of other isoforms, such as y- and &-tocopherol, in commercial preparations of vitamin E may account for the inconsistent results of clinical trials. Since platelet aggregation is intimately involved in thrombogenesis, the relative effects of ox-, y-, and 6-tocopherol and their combination were examined on human platelet aggregation, lipid peroxidation, and constitutive nitric oxide synthase (cNOS) activity. Methods and Results: Human platelets were incubated with the three different isoforms of tocopherol and their combination for 30 minutes, and then ADP-induced platelet aggregation measured. All three isoforms of tocopherol markedly and similarly decreased platelet aggregation in a concentration (120-480,uM)-dependent manner. All three tocopherols also decreased the level of the lipid peroxidation product, malondialdehyde (MDA), and increased NO release (P < 0.05 vs control). These isoforms of tocopherol did not affect cNOS protein expression, but enhanced cNOS phosphorylation in platelets. The combination of three tocopherols in a concentration found in nature was more potent than oc-, y-, or 6-tocopherol alone in this regard. Conclusion: These observations suggest that all three major isoforms of tocopherol have a similar effect on human platelet aggregation. The three isoforns appear to attenuate platelet aggregation at least in part via a decrease in free radical generation and an increase in platelet cNOS activity. The combination of tocopherols has a synergistic platelet inhibitory effect. Future clinical trials should concentrate on the combination of these three isoforms of tocopherols

    High photo-excited carrier multiplication by charged InAs dots in AlAs/GaAs/AlAs resonant tunneling diode

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    We present an approach for the highly sensitive photon detection based on the quantum dots (QDs) operating at temperature of 77K. The detection structure is based on an AlAs/GaAs/AlAs double barrier resonant tunneling diode combined with a layer of self-assembled InAs QDs (QD-RTD). A photon rate of 115 photons per second had induced 10nA photocurrent in this structure, corresponding to the photo-excited carrier multiplication factor of 10^7. This high multiplication factor is achieved by the quantum dot induced memory effect and the resonant tunneling tuning effect of QD-RTD structure.Comment: 10 pages,5 figures. Submitted to Applied Physics Letter

    An integrated factor analysis model for product eco-design based on full life cycle assessment

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    Purpose: Among the methods of comprehensive analysis for a product or an enterprise, there exist defects and deficiencies in traditional standard cost analyses and life cycle assessment methods. For example, some methods only emphasize one dimension (such as economic or environmental factors) while neglecting other relevant dimensions. This paper builds a factor analysis model of resource value flow, based on full life cycle assessment and eco-design theory, in order to expose the relevant internal logic between these two factors. Design/methodology/approach: The model considers the efficient multiplication of resources, economic efficiency, and environmental efficiency as its core objectives. The model studies the status of resource value flow during the entire life cycle of a product, and gives an in-depth analysis on the mutual logical relationship of product performance, value, resource consumption, and environmental load to reveal the symptoms and potentials in different dimensions. Findings: This paper illustrates logical relationships among resource efficiency, economic efficiency and environmental efficiency, builds a fully comprehensive evaluation analysis model to trace, evaluate and analyze the status of the material and value flow of the product life cycle process. Originality/value: This provides comprehensive, accurate and timely decision-making information for enterprise managers regarding product eco-design, as well as production and management activities. To conclude, it verifies the availability of this evaluation and analysis model using a Chinese SUV manufacturer as an example.Peer Reviewe

    Photoresponse of Long-Wavelength AlGaAs/GaAs Quantum Cascade Detectors

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    We study the photoresponse and photocurrents of long-wavelength infrared quantum cascade detectors (QCDs) based on AlGaAs/GaAs material system. The photocurrent spectra were measured at different temperatures from 20 K to 100 K with a low noise Fourier transforming infrared spectrometer. The main response peak appeared at 8.9 μm while four additional response peaks from 4.5 μm to 10.1 μm were observed as well. We confirmed that the photocurrent comes from phonon assisted tunneling and the multipeak behavior comes from the complicated optical transition in the quantum cascade structure. This work is valuable for the future design and optimization of QCD devices

    Facilitative interaction between angiotensin II and oxidised LDL in cultured human coronary artery endothelial cells

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    Background Several studies have shown that angiotensin II (Ang II) and oxidised low-density lipoprotein (ox-LDL) are critical factors in atherosclerosis. In this study, we examined the molecular basis of mutually facilitative interactions between Ang II and ox-LDL in human coronary artery endothelial cells (HCAECs). Methods and results We observed that incubation of cultured HCAECs with Ang II (10-12 to 10-6 M) for 24 hours caused a concentration-dependent increase in the expression of mRNA and protein of a specialised receptor for ox-LDL (LOX-1). These effects of Ang II were completely blocked by pretreatment of HCAECs with candesartan (10-6 M), a specific AT1-receptor blocker, but not by PD 123319 (10-6 M), a specific AT2-receptor blocker. On the other hand, incubation of HCAECs with ox-LDL (10 and 40 µg/ml) for 24 hours progressively upregulated AT1-, but not AT 2-, receptor mRNA and protein. Pretreatment of cells with the anti-oxidant alpha-tocopherol (1—5 x 10-6 M) inhibited the upregulation of AT1-receptor expression induced by ox-LDL (p<0.05). To determine the significance of expression of AT1-receptors and LOX-1, we measured cell injury in response to Ang II and ox-LDL. Incubation of cells with both ox-LDL and Ang II synergistically increased cell injury, measured as cell viability and LDH release, compared with either ox-LDL or Ang II alone (both p<0.05). Alpha-tocopherol, as well as candesartan, attenuated cell injury in response to Ang II and ox-LDL (both p<0.05). Conclusions These observations show that Ang II upregulates a novel endothelial receptor for ox-LDL (LOX-1) gene expression and ox-LDL in turn upregulates Ang II AT 1receptor gene expression. This interaction between Ang II and ox-LDL further augments cell injury in HCAECs. These findings provide basis for the use of AT1-receptor blockers and anti-oxidants in designing therapy for atherosclerosis and myocardial ischaemia
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