2,352 research outputs found

    Using nano silica to enhance the performance of recycled asphalt mixtures

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    Understanding how the physical properties of Nano-silica material affect the ultimate implementation of the asphalt binder is an essential study area that has been disregarded previously. The current investigation aims to determine whether or not it was possible to change the asphalt binder with Nano-silica (NS) depending on the qualities of the asphalt binder under consideration. Using nano-silica (2, 4, and 6 percentage by weight of asphalt), a penetration grade asphalt cement with 60/70 was developed. Nano silica and asphalt cement were first tested for their qualities. The NS modified asphalt binder was ready for use in the experiment after being heated to 160°C and mixed with a shear mixer at 2000 rpm for 60 minutes. The softening point temperature and penetration index of the NS modified asphalt binder, as well as the Brookfield rotational viscosity and ductility data, were also evaluated. Based on the rheological performance of the NS modified asphalt binder, increasing Nano silica content increases stiffness while decreasing temperature sensitivity. The addition of 4% Nano silica (NS) asphalt binder improved its basic properties and allowed it to be used in hot weather. By adding 4% NS to the hot recycle asphalt mixture, the Marshall stability is increased by 32.5%, the flow is reduced by 21.4%, the unit weight is maintained, and the amount of air voids in the mix, as well as other mix qualities, are kept at acceptable ranges. It'll also boost the ITS by 37.8%. In general, adding NS to asphalt mixtures improves their qualities

    A deep learning enabler for non-intrusive reduced order modeling of fluid flows

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    In this paper, we introduce a modular deep neural network (DNN) framework for data-driven reduced order modeling of dynamical systems relevant to fluid flows. We propose various deep neural network architectures which numerically predict evolution of dynamical systems by learning from either using discrete state or slope information of the system. Our approach has been demonstrated using both residual formula and backward difference scheme formulas. However, it can be easily generalized into many different numerical schemes as well. We give a demonstration of our framework for three examples: (i) Kraichnan-Orszag system, an illustrative coupled nonlinear ordinary differential equations, (ii) Lorenz system exhibiting chaotic behavior, and (iii) a non-intrusive model order reduction framework for the two-dimensional Boussinesq equations with a differentially heated cavity flow setup at various Rayleigh numbers. Using only snapshots of state variables at discrete time instances, our data-driven approach can be considered truly non-intrusive, since any prior information about the underlying governing equations is not required for generating the reduced order model. Our \textit{a posteriori} analysis shows that the proposed data-driven approach is remarkably accurate, and can be used as a robust predictive tool for non-intrusive model order reduction of complex fluid flows.Comment: 36 pages, 21 figure

    Molecular mechanisms involved in human platelet aggregation by synergistic interaction of platelet-activating factor and 5-hydroxytryptamine

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    Our recent studies have shown that co-activation of Gq and Gi proteins by 5-hydroxytryptamine (5-HT) and adrenaline show synergism in human platelet aggregation. This study was conducted to examine the mechanism(s) of synergistic interaction of 5-HT and platelet activating factor (PAF) in human platelets. We show that PAF, but not 5-HT, increased platelet aggregation in a concentration-dependent manner. However, low concentrations of 5-HT (2 microM) potentiated platelet aggregation induced by subthreshold concentration of PAF (40 nM) indicating a synergistic interaction between the two agonists and this synergism was blocked by receptor antagonists to either 5-HT or PAF. 5-HT also potentiated the effect of PAF on thromboxane A2 (TXA2) formation and phosphorylation of extracellularly regulated mitogen-activated protein kinases (ERK1/2). The synergism of 5-HT and PAF in platelet aggregation was inhibited by calcium (Ca2+) channel blockers, verapamil and diltiazem, phospholipase C (PLC) inhibitor, U73122, cyclooxygenase (COX) inhibitor, indomethacin, and MEK inhibitor, PD98059. These data suggest that synergistic effect of 5-HT and PAF on human platelet aggregation involves activation of PLC/Ca2+, COX and MAP kinase pathways

    The patient safety practices of emergency medical teams in disaster zones: a systematic analysis

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    Introduction: Disaster zone medical relief has been criticised for poor quality care, lack of standardisation and accountability. Traditional patient safety practices of Emergency Medical Teams (EMT) in disaster zones were not well understood. Improving the quality of healthcare in disaster zones has gained importance within global health policy. Ascertaining patient safety practices of EMTs in disaster zones may identify areas of practice that can be improved. Methods: A systematic search of OvidSP, Embase and Medline databases, key journals of interest, key grey-literature texts, the databases of the World Health Organisation (WHO), Médecins Sans Frontieres (MSF) and the International Committee of the Red Cross (ICRC), and Google Scholar were performed. Descriptive studies, case reports, case series, prospective trials and opinion pieces were included with no limitation on date or language of publication. Results: There were 9,685 records, evenly distributed between the peer-reviewed and grey literature. Of these, 30 studies and 9 grey literature texts met the inclusion criteria and underwent qualitative synthesis. From these articles, 302 patient safety statements were extracted. Thematic analysis categorised these statements into 84 themes (total frequency 632). The most frequent themes were limb injury (9%), medical records (5.4%), surgery decision making (4.6%), medicines safety (4.4%) and protocol (4.4%) Conclusion: Patient safety practices of EMTs in disaster zones are weighted towards acute clinical care, particularly surgery. The management of Non-Communicable Disease (NCD) is underrepresented. There is widespread recognition of the need to improve medical record keeping. High-quality data and institutional level patient safety practices are lacking. There is no consensus on disaster zone specific performance indicators. These deficiencies represent opportunities to improve patient safety in disaster zones

    Predictors of short-term readmission after beyond total mesorectal excision for primary locally advanced and recurrent rectal cancer

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    Unplanned readmissions heavily affect the cost of health care and are used as an indicator of performance. No clear data are available regarding beyond-total mesorectal excision (bTME) procedure. Aim of the study is to identify patient-related and surgery-related factors influencing the 30-day readmissions after bTME. Retrospective data were collected from 220 patients who underwent bTME procedures at single centre between 2006 and 2016. Patient-related and operative factors were assessed, including body mass index (BMI), age, gender, American Society of Anaesthesiologists’ (ASA) score, preoperative stage, neo-adjuvant therapy, primary tumour vs recurrence, the extent of surgery. The readmission rate was 8.18%. No statistically significant association was found with BMI, ASA score, length of stay and stay in the intensive care unit, primary vs recurrent tumour or blood transfusions. Not quite statistically significant was the association with pelvic side wall dissection (OR 3.32, p = 0.054). Statistically significant factors included preoperative stage > IIIb (OR: 4.77, p = 0.002), neo-adjuvant therapy (OR: 0.13, p = 0.0006), age over 65 years (OR: 5.96, p = 0.0005), any re-intervention during the first admission (OR: 7.4, p = 0.0001), and any post-operative complication (OR: 9.01, p = 0.004). The readmission rate after beyond-TME procedure is influenced by patient-related factors as well as post-operative morbidity

    Using Datamining Techniques to Help Metaheuristics: A Short Survey

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    International audienceHybridizing metaheuristic approaches becomes a common way to improve the efficiency of optimization methods. Many hybridizations deal with the combination of several optimization methods. In this paper we are interested in another type of hybridization, where datamining approaches are combined within an optimization process. Hence, we propose to study the interest of combining metaheuristics and datamining through a short survey that enumerates the different opportunities of such combinations based on literature examples

    Digital health and inequalities in access to health services in Bangladesh: Mixed methods study

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    Background: Globally, the rapid growth of technology and its use as a development solution has generated much interest in digital health. In line with global trends, Bangladesh is also integrating technology into its health system to address disparities. Strong political endorsement and uptake of digital platforms by the government has influenced the rapid proliferation of such initiatives in the country. This paper aims to examine the implications of digital health on access to health care in Bangladesh, considering who uses electronic devices to access health information and services and why. Objective: This study aims to understand how access to health care and related information through electronic means (digital health) is affected by sociodemographic determinants (ie, age, gender, education, socioeconomic status, and personal and household ownership of mobile phones) in a semiurban community in Bangladesh. Methods: A cross-sectional survey of 854 households (between October 2013 and February 2014) and 20 focus group discussions (between February 2017 and March 2017) were conducted to understand (1) who owns electronic devices; (2) who, among the owners, uses these to access health information and services and why; (3) the awareness of electronic sources of health information; and (4) the role of intermediaries (family members or peers who helped to look for health information using electronic devices). Results: A total of 90.3% (771/854) of households (471/854, 55.2% of respondents) owned electronic devices, mostly mobile phones. Among these, 7.2% (34/471) used them to access health information or services. Middle-aged (35-54 years), female, less (or not) educated, and poorer people used these devices the least (α=.05, α is the level of significance). The lack of awareness, discomfort, differences with regular care-seeking habits, lack of understanding and skills, and proximity to a health facility were the main reasons for not using devices to access digital health. Conclusions: Although influenced by sociodemographic traits, access to digital health is not merely related to device ownership and technical skill. Rather, it is a combination of general health literacy, phone ownership, material resources, and technical skill as well as social recognition of health needs and inequity. This study’s findings should serve as a basis for better integrating technology within the health system and ensuring equitable access to health care

    Enhancement of Physical Properties of Asphalt Binder by Using Silica Powder

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    One of the primary requirements for a successful pavement system can be regarded as the caliber of the road pavement. Therefore, various measures have been taken, such as improving pavement quality and structure design methods, to reduce the issues of fatigue cracks and rutting of roads. Since a few years ago, engineers have paid more attention to modifying and improving the performance of asphalt by adding various additives to improve the environment and lower the price of modified pavement mixture. Evaluation of employing modified asphalt cement at various percentages of particle size of silica powder is the main goal of this study. Three percentages of Particle Size of Silica Powder Nano silica and micro silica with 2, 4, and 6% of the weight of asphalt as a modifier for asphalt and their effect on the performance of asphalt mixtures at high temperatures. It was discovered that adding silica powder to asphalt cement would increase the softening point and viscosity and decrease ductility and penetration. Experimental results indicated that the Silica Powder positively contributed to the performance properties of asphalt
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