233 research outputs found

    Evaluation and Identification of Cracking Susceptibility of Asphalt Binders and Mixtures by Incorporation of Effects of Aging on Performance

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    An important aspect which causes a significant effect on performance of asphalt materials is aging. With increase of aging, asphalt materials lose their relaxation capabilities and becomes more susceptible to cracking. Thus, an improved understanding of how aging impacts the cracking behavior of asphalt materials will allow for design of more reliable and durable asphalt pavements. In this study, different laboratory aging levels were performed to simulate different periods of pavement service life. Various performance tests (including Complex Modulus (E*), Simplified Viscoelastic Continuum Damage (S-VECD), Semi Circular Bending (SCB) and Disk Shaped Compact Tension (DCT) tests for asphalt mixtures; Frequency and Temperature Sweep test using a Dynamic Shear Rheometer (DSR) with 4mm plate and Linear Amplitude Sweep (LAS) test for asphalt binders) were conducted to evaluate the changes of material’s properties (including fundamental viscoelastic/rheological property, fatigue characterization, and fracture behavior) over time. The advanced Mechanistic-Empirical (ME) Models (FlexPAVE and IlliTC) were also employed to simulate the aging effects using the predicted fatigue and thermal cracking performance of asphalt mixtures in context of pavement structure, traffic and climatic conditions. The performance tests and simulation models provided a way to quantify the effects of aging on cracking behavior of asphalt materials and they can estimate the roles of various mixture variables on the cracking performance. Based on the testing and simulation results, this study also (1) developed new performance indices to evaluate the fatigue performance of asphalt binders with aging; (2) developed a rheological-based mixture aging model to evaluate cracking and aging susceptibility of asphalt mixtures over time; (3) provided insights on the relationships between binder and mixture cracking behaviors. This dissertation makes a contribution in improvement of the approaches for evaluation of cracking potential of asphalt pavements and allows for assessment of different mixtures at early stage of material selection and mixture design

    How do self-exempt beliefs affect intentions to quit smoking? An exploration of the mediating role of threat appraisal and coping appraisal

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    IntroductionNumerous smokers are cognizant of the detrimental effects associated with this habit yet exhibit a persistent reluctance to cease their tobacco consumption. Self-exempt beliefs serve as an obstacle to the cessation of this addictive behavior. This research explored the impact of self-exempt beliefs on the readiness to quit smoking based on the Protection Motivation Theory (PMT) model and the mediating roles of threat appraisal and coping appraisal.MethodsSelf-exempt beliefs, PMT constructs, and the intention to quit smoking constituted the theoretical model. The questionnaires were collected from 488 Chinese adult male smokers based on snowball sampling. Exploratory Factor Analysis (EFA) was used to examine the underlying factor structure of the pre-designed self-exempt beliefs scale. The reliability, validity, path coefficients, and explanatory power of the model were calculated using Partial Least Squares Structural Equation Modeling (PLS-SEM).Results and discussionThe results showed that : (1) three common factors (skeptic beliefs, bulletproof beliefs, and “worth it” beliefs) with a total of 11 items were retained after EFA; (2) skeptic beliefs and “worth it” beliefs had a significantly negative effect on both threat appraisal and coping appraisal, while bulletproof beliefs did not; (3) bulletproof beliefs had a significantly positive direct impact on intention to quit, “worth it” beliefs had a significantly negative direct impact on intention, while skeptic beliefs had no significantly direct impact on intention; (4) threat appraisal and coping appraisal positively and significantly predicted cessation intention; and (5) threat appraisal and coping appraisal, as two main cognitive processes, acted as full mediations between skeptic beliefs and the intention to quit, as complementary partial mediations between “worth it” beliefs and the intention, and as non-mediation between bulletproof beliefs and the intention. Our findings suggest that efforts to undermine or “prevent” these self-exempt beliefs, particularly “worth it” and skeptic beliefs, may be an effective tactic for health communication interventions for quitting smoking

    The Organic Amendment Improve the Yield and Quality of Vegetable

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    Using biotechnology, we can change agricultural wastes into high‐quality organic fertilizers, which leads us in the direction of the development in modern agriculture and act as substitute to the chemical fertilizers. In this chapter, five types of technologies of organic amendment are elaborated. Each method can be selected based on the specific circumstance. The effects of the technology in the production are introduced and the principles of the technologies are explained in a simple manner

    Thymoquinone and cisplatin as a therapeutic combination in lung cancer: In vitro and in vivo

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    <p>Abstract</p> <p>Background</p> <p>Thymoquinone (TQ) is a compound extracted from Black Caraway seeds of <it>Nigella Sativa </it>and is active against various cancers. Cisplatin (CDDP) is the most active chemotherapeutic agent in Lung Cancer. Here we report activity of TQ against non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) cell lines alone and in combination with Cisplatin (CDDP).</p> <p>Methods</p> <p>For proliferation MTT assay, cell viability trypan blue assay and for apoptosis Annexin-V FITC assay were used in NCI-H460 and NCI-H146 cell lines. Inhibition of invasion by TQ was assessed using Matrigel assay and its affect on release of various cytokines was determined using RayBio Human Cytokine detection kit. Mouse xenograft model using NCI-H460 was used to determine <it>in vivo </it>activity of TQ and CDDP. Inhibition of LPS induced NF-κB expression by TQ was determined using transgenic mice expressing a luciferase reporter.</p> <p>Results</p> <p>TQ was able to inhibit cell proliferation, reduce cell viability and induce apoptosis. TQ at 100 μM and CDDP at 5 μM inhibited cell proliferation by nearly 90% and the combination showed synergism. TQ was able to induced apoptosis in both NCI-H460 and NCI-H146 cell lines. TQ also appears to affect the extracellular environment inhibiting invasion and reducing the production of two cytokines ENA-78 and Gro-alpha which are involved in neo-angiogenesis. Using a mouse xenograft model we were able to demonstrate that combination of TQ and CDDP was well tolerated and significantly reduced tumor volume and tumor weight without additional toxicity to the mice. In the combination arms (TQ5 mg/kg/Cis 2.5 mg/kg) tumor volume was reduced by 59% and (TQ20 mg/kg/Cis 2.5 mg/kg) by 79% as compared to control which is consistent with <it>in vitro </it>data. TQ down regulated NF-κB expression which may explain its various cellular activities and this activity may prove useful in overcoming CDDP resistance from over expression of NF-κB.</p> <p>Conclusions</p> <p>Thus TQ and CDDP appear to be an active therapeutic combination in lung cancer.</p

    Acute Effects of Particulate Air Pollution on Ischemic Stroke and Hemorrhagic Stroke Mortality

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    Background and Purpose: A large body of literature reported the association of particulate matter (PM) with stroke in high-income countries. Few studies have examined the association between PM and stroke in middle- and low-income countries and considered the types of stroke. In this study, we examined the short-term effects of particulate matter &lt;2.5 μm in diameter (PM2.5) and particulate matter &lt;10 μm in diameter (PM10) on ischemic stroke mortality and hemorrhagic stroke mortality in Beijing, China.Methods: We used an ecological study design and quasi-Poisson generalized additive models to evaluate the association of PM2.5 and PM10 and cerebrovascular diseases mortality, as well as ischemic- and hemorrhagic stroke mortality. In the model, we controlled long-term and season trends, temperature, and relative humidity, the day of the week and air pollution. For cerebrovascular diseases mortality, we examined the effects stratified by sex and age with different lag days.Results: A total of 48,122 deaths for cerebrovascular disease (32,799 deaths for ischemic stroke and 13,051 deaths for hemorrhagic stroke) were included in the study. PM2.5 was associated with stroke mortality. The 10 μg/m3 increase of PM2.5 was associated with the increase of mortality, 0.27% (95% CI, 0.12–0.43%) for cerebrovascular diseases, 0.23% (95% CI, 0.04–0.42%) for ischemic stroke and 0.37% (95% CI, 0.07–0.67%) for hemorrhagic stroke -. The associations between PM10 and mortality were also detected for cerebrovascular diseases and ischemic stroke, but not in hemorrhagic stroke. The stratified analysis suggested age and gender did not modify the effects of PM on mortality significantly.Conclusions: Our study suggested that short-term exposure to ambient PM was associated with the risk of stroke mortality

    YGR198w (YPP1) targets A30P α-synuclein to the vacuole for degradation

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    Using a genetic screen we discovered that YGR198w (named YPP1), which is an essential Saccharomyces cerevisiae gene of unknown function, suppresses the toxicity of an α-synuclein (α-syn) mutant (A30P) that is associated with early onset Parkinson's disease. Here, we show that YPP1 suppresses lethality of A30P, but not of wild-type α-syn or the A53T mutant. The Ypp1 protein, when overexpressed, drives each of the three α-syns into vesicles that bud off the plasma membrane, but only A30P-containing vesicles traffick to and merge with the vacuole, where A30P is proteolytically degraded. We show that Ypp1p binds to A30P but not the other two α-syns; that YPP1 interacts with genes involved in endocytosis/actin dynamics (SLA1, SLA2, and END3), protein sorting (class E vps), and vesicle-vacuole fusion (MON1 and CCZ1) to dispose of A30P; and that YPP1 also participates in pheromone-triggered receptor-mediated endocytosis. Our data reveal that YPP1 mediates the trafficking of A30P to the vacuole via the endocytic pathway
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