2,225 research outputs found

    Modelling Selective Catalytic Reduction (SCR) of NOx to N2 over Cu-SSZ-13

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    Modelling Selective Catalytic Reduction (SCR) of NOx to N2 over Cu-SSZ-13 Reduction of NOx emissions from diesel engine exhaust is an environmental issue driven by increasingly stringent emission regulations. Cu-SSZ-13 catalysts have been shown to be promising for this application due to their hydrothermal stability and selectivity in reducing NOx to N2using NH3 compared to other zeolite catalysts. SOx formed from the combustion of ppm levels of sulfur in diesel fuel deactivates the Cu-SSZ-13 catalyst. However, its effect on Cu2+ and CuOH active sites and the SCR mechanism is unclear and under debateUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Do Border Crossings Contribute to Underage Motor-Vehicle Fatalities?

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    Currently, Michigan residents can avoid the national drinking age of 21 by crossing into Ontario where the drinking age is 19. This paper explores the impact that border crossings, connecting areas with different minimum legal drinking ages (MLDA), have on motor-vehicle fatalities. We analyze border crossings connecting Michigan to Ontario, as well as to its surrounding states in the period in which Michigan’s MLDA was raised to 21. Using a “differences-in-differences-in-differences” approach we find that the MLDA change did not contribute to increased underage fatalities in border crossing counties.

    The growing threat of gonococcal blindness

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    Antibiotic-resistant gonorrhea is now a reality, as well as the consequences of untreatable infections. Gonococcal eye infections result in blindness if not properly treated; they accounted for the vast majority of infections in children in homes for the blind in the pre-antibiotic era. Neisseria gonorrhoeae infects the eyes of infants born to mothers with gonorrhea and can also infect the eyes of adults. Changes in sexual practices may account for the rise in adult gonococcal eye infections, although some cases seem to have occurred with no associated genital infection. As gonorrhea becomes increasingly difficult to treat, the consequences for the treatment of gonococcal blindness must be considered as well. Monocaprin was shown to be effective in rapidly killing N. gonorrhoeae, and is non-irritating in ocular models. Repeated passage in sub-lethal monocaprin induces neither resistance in gonococci nor genomic mutations that are suggestive of resistance. Here, we show that 1mMmonocaprin kills 100% of N. gonorrhoeae in 2 min, and is equally effective against N. meningitidis, a rare cause of ophthalmia neonatorum that is potentially lethal. Monocaprin at 1mMalso completely kills Staphylococcus aureus after 60 min, and 25 mM kills 80% of Pseudomonas aeruginosa after 360 min. Previously, 1 mM monocaprin was shown to eliminate Chlamydia trachomatis in 5 min. Monocaprin is, therefore, a promising active ingredient in the treatment and prophylaxis of keratitis, especially considering the growing threat of gonococcal blindness due to antimicrobial resistance

    Cortisol patterns are associated with T cell activation in HIV.

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    ObjectiveThe level of T cell activation in untreated HIV disease is strongly and independently associated with risk of immunologic and clinical progression. The factors that influence the level of activation, however, are not fully defined. Since endogenous glucocorticoids are important in regulating inflammation, we sought to determine whether less optimal diurnal cortisol patterns are associated with greater T cell activation.MethodsWe studied 128 HIV-infected adults who were not on treatment and had a CD4(+) T cell count above 250 cells/µl. We assessed T cell activation by CD38 expression using flow cytometry, and diurnal cortisol was assessed with salivary measurements.ResultsLower waking cortisol levels correlated with greater T cell immune activation, measured by CD38 mean fluorescent intensity, on CD4(+) T cells (r = -0.26, p = 0.006). Participants with lower waking cortisol also showed a trend toward greater activation on CD8(+) T cells (r = -0.17, p = 0.08). A greater diurnal decline in cortisol, usually considered a healthy pattern, correlated with less CD4(+) (r = 0.24, p = 0.018) and CD8(+) (r = 0.24, p = 0.017) activation.ConclusionsThese data suggest that the hypothalamic-pituitary-adrenal (HPA) axis contributes to the regulation of T cell activation in HIV. This may represent an important pathway through which psychological states and the HPA axis influence progression of HIV

    Rapid-Scan Operando Infrared Spectroscopy

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    Novel methodology, referred to as rapid-scan operando, has been demonstrated to be a highly powerful tool for studying reaction mechanisms in heterogeneous catalysis, because it combines rapid scan for IR monitoring in the milliseconds time frame and operando methodology. As proof of concept, the NOx–CO and NOx–H2 reactions were studied as model catalyzed reactions with practical interest for removal of NOx in diesel exhausts. Rapid-scan operando experiments confirmed state-of-the-art knowledge concerning the reaction mechanisms and, more importantly, allowed us to elucidate, for the first time, the different roles of the surface hydroxy groups depending on the reductant used (CO or H2). Moreover, this new tool was used to distinguish the behavior of carbonates and nitrites under reaction conditions that could not be monitored by conventional IR spectroscopy approaches owing to overlap of their absorbance bands.Financial support from Generalitat Valenciana (Project PROMETEOII/2014/010 and grant BEST/2014/250), Spanish Ministry of Economy and Competitiveness (Projects CTQ2012–30703 and MAT2014–61992-EXP, and grant PRX14/00249), and the European Union (FEDER funding)

    Screening for Gynecologic Conditions With Pelvic Examination US Preventive Services Task Force Recommendation Statement

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    IMPORTANCE Many conditions that can affect women\u27s health are often evaluated through pelvic examination. Although the pelvic examination is a common part of the physical examination, it is unclear whether performing screening pelvic examinations in asymptomatic women has a significant effect on disease morbidity and mortality. OBJECTIVE To issue a new US Preventive Services Task Force(USPSTF) recommendation on screening for gynecologic conditions with pelvic examination for conditions other than cervical cancer, gonorrhea, and chlamydia, for which the USPSTF has already made specific recommendations. EVIDENCE REVIEW The USPSTF reviewed the evidence on the accuracy, benefits, and potential harms of performing screening pelvic examinations in asymptomatic, nonpregnant adult women 18 years and older who are not at increased risk for any specific gynecologic condition. FINDINGS Overall, the USPSTF found inadequate evidence on screening pelvic examinations for the early detection and treatment of a range of gynecologic conditions in asymptomatic, nonpregnant adult women. CONCLUSIONS AND RECOMMENDATION The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of performing screening pelvic examinations in asymptomatic, nonpregnant adult women. (I statement) This statement does not apply to specific disorders for which the USPSTF already recommends screening (ie, screening for cervical cancer with a Papanicolaou smear, screening for gonorrhea and chlamydia)

    Effort-related motivational effects of the pro-inflammatory cytokine interleukin 1-beta: studies with the concurrent fixed ratio 5/ chow feeding choice task

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    Rationale. Effort-related motivational symptoms such as anergia and fatigue are common in patients with depression and other disorders. Research implicates pro-inflammatory cytokines in depression, and administration of cytokines can induce effort-related motivational symptoms in humans. Objectives. The present experiments focused on the effects of the pro-inflammatory cytokine interleukin 1-beta (IL-1β) on effort-related choice behavior. Methods. Rats were tested on a concurrent fixed ratio 5 lever pressing/chow feeding choice procedure, which assesses the tendency of rats to work for a preferred food (high carbohydrate pellets) in the presence of a concurrently available but less preferred substitute (laboratory chow). Results. IL-1β (1.0–4.0 μg/kg IP) shifted choice behavior, significantly decreasing lever pressing and increasing intake of the freely available chow. The second experiment assessed the ability of the adenosine A2A antagonist (E)-phosphoric acid mono-[3-[8-[2-(3-methoxyphenyl)vinyl]-7-methyl-2,6-dioxo-1-prop-2-ynyl-1,2,6,7-tetrahydropurin-3-yl] propyl] ester disodium salt (MSX-3) to reverse the behavioral effects of IL-1β. MSX-3 attenuated the effort-related impairments produced by IL-1β, increasing lever pressing and also decreasing chow intake. In the same dose range that shifted effort-related choice behavior, IL-1β did not alter food intake or preference in parallel free-feeding choice studies, indicating that these low doses were not generally suppressing appetite or altering preference for the high carbohydrate pellets. In addition, IL-1β did not affect core body temperature. Conclusions. These results indicate that IL-1β can reduce the tendency to work for food, even at low doses that do not produce a general sickness, malaise, or loss of appetite. This research has implications for the involvement of cytokines in motivational symptoms such as anergia and fatigue
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