48 research outputs found

    Towards control of the size, composition and surface area of NiO nanostructures by Sn doping

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    Achieving nanostructures with high surface area is one of the most challenging tasks as this metric usually plays a key role in technological applications, such as energy storage, gas sensing or photocatalysis, fields in which NiO is gaining increasing attention recently. Furthermore, the advent of modern NiO-based devices can take advantage of a deeper knowledge of the doping process in NiO, and the fabrication of p-n heterojunctions. By controlling experimental conditions such as dopant concentration, reaction time, temperature or pH, NiO morphology and doping mechanisms can be modulated. In this work, undoped and Sn doped nanoparticles and NiO/SnO_2 nanostructures with high surface areas were obtained as a result of Sn incorporation. We demonstrate that Sn incorporation leads to the formation of nanosticks morphology, not previously observed for undoped NiO, promoting p-n heterostructures. Consequently, a surface area value around 340 m^2/g was obtained for NiO nanoparticles with 4.7 at.% of Sn, which is nearly nine times higher than that of undoped NiO. The presence of Sn with different oxidation states and variable Ni^(3+)/Ni^(2+) ratio as a function of the Sn content were also verified by XPS, suggesting a combination of two charge compensation mechanisms (electronic and ionic) for the substitution of Ni^(2+) by Sn^(4+). These results make Sn doped NiO nanostructures a potential candidate for a high number of technological applications, in which implementations can be achieved in the form of NiO-SnO_2 p-n heterostructures

    Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

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    Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

    THE INFLUENCE OF FRUSTRATION TOLERANCE LEVELS AND PERFORMANCE FEEDBACK ON LEARNING OUTCOMES

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    Bachelor'sBachelor of Social Sciences (Honours

    Differential persuasive effects of high and low credibility sources on Singapore and China individual investors' judgement.

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    With the proliferation of investment information, investors are likely to have repeated exposure to similar information from sources with varying credibility. Contrary to main effects studies, psychology research has found that low credibility source may interact with other factors to be more persuasive than high credibility source. Our experimental results, using Singapore accountancy undergraduates as participants, indicate that for individual investor holding an initial negative position, negative news from a low credibility source is more persuasive than a high credibility source. Furthermore, repeating similar negative news from another low credibility source enhances the overall persuasiveness of the news regardless of whether the first exposure to the news is from a high or low credibility source, although the effect is stronger for the former. With repeated exposure from a high credibility source, we obtained weak support on the decrease in overall persuasiveness when the initial source credibility is low and opposite result when the initial source credibility is high. All the above results were obtained (except that the effects were stronger) when we replicated the experiment conditions using China participants

    Combining the Grisotti Flap With a Secondary Dermoglandular Pedicle for Partial Breast Reconstruction Following Contiguous Central-Inferior Segment Breast Cancer Excision.

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    A 61-year-old patient (38DD) with multifocal invasive ductal carcinomas requested breast-conserving surgery. An innovative two pedicle combination using a laterally-based Grisotti flap and an inferomedially-based secondary pedicle was designed to reconstruct a combined central breast (NAC included) and inferior segment resection defect. Satisfactory cosmesis with clear resection margins was achieved
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