279 research outputs found

    Quasi-3D Hyperbolic Shear Deformation Theory for the Free Vibration Study of Honeycomb Microplates with Graphene Nanoplatelets-Reinforced Epoxy Skins

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    A novel quasi-3D hyperbolic shear deformation theory (QHSDT) with five unknowns is here employed, together with the Hamilton's principle and the modified couple stress theory (MCST) to analyze the vibrational behavior of rectangular micro-scale sandwich plates resting on a visco-Pasternak foundation. The sandwich structure features a Nomex or Glass phenolic honeycomb core, and two composite face sheets reinforced with graphene nanoplatelets (GPLs). The effective properties of both face sheets are evaluated by means of the Halpin-Tsai and extended rule of mixture (ERM) micromechanical schemes. The governing equations of the problem are derived by applying the Hamilton's principle, whose solutions are determined theoretically according to a classical Navier-type procedure. A parametric study checks for the effect of different material properties, length-scale parameters, foundation parameters and geometrical properties of the honeycomb cells, and the reinforcing GPLs, on the vibration response of the layered structure, which can be of great interest for many modern engineering applications and their optimization design

    COVID-19 Induced Myocarditis: A Rare Cause of Heart Failure.

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    Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing lung injury has been well documented in the literature recently. They do so primarily by binding to the membrane-bound form of angiotensin-converting enzyme 2 (ACE-2) receptors. However, since these receptors are also expressed in the heart and blood vessels, coronavirus can also cause damage to these organs by binding to the ACE-2 receptors. A typical case of coronavirus disease 2019 (COVID-19) usually presents with respiratory symptoms like cough and shortness of breath accompanied by fever. The literature regarding this pandemic has been growing and now we know very well that the effect of this deadly virus is not restricted to the lungs alone. It can, unfortunately, cause various other complications ranging from neurological damage to even myocardial injury in rare cases. We present an interesting case of a 40-year-old male patient who presented to us with shortness of breath. When further investigated, the patient was found to have a new onset of heart failure secondary to COVID-19 induced myocarditis

    Fungal Endophytes to Combat Biotic and Abiotic Stresses for Climate-Smart and Sustainable Agriculture

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    The agricultural sustainability concept considers higher food production combating biotic and abiotic stresses, socio-economic well-being, and environmental conservation. On the contrary, global warming-led climatic changes have appalling consequences on agriculture, generating shifting rainfall patterns, high temperature, CO2, drought, etc., prompting abiotic stress conditions for plants. Such stresses abandon the plants to thrive, demoting food productivity and ultimately hampering food security. Though environmental issues are natural and cannot be regulated, plants can still be enabled to endure these abnormal abiotic conditions, reinforcing the stress resilience in an eco-friendly fashion by incorporating fungal endophytes. Endophytic fungi are a group of subtle, non-pathogenic microorganisms establishing a mutualistic association with diverse plant species. Their varied association with the host plant under dynamic environments boosts the endogenic tolerance mechanism of the host plant against various stresses via overall modulations of local and systemic mechanisms accompanied by higher antioxidants secretion, ample enough to scavenge Reactive Oxygen Species (ROS) hence, coping over-expression of defensive redox regulatory system of host plant as an aversion to stressed condition. They are also reported to ameliorate plants toward biotic stress mitigation and elevate phytohormone levels forging them worthy enough to be used as biocontrol agents and as biofertilizers against various pathogens, promoting crop improvement and soil improvement, respectively. This review summarizes the present-day conception of the endophytic fungi, their diversity in various crops, and the molecular mechanism behind abiotic and biotic resistance prompting climate-resilient aided sustainable agriculture.Peer reviewe

    Nosocomial infection in an Iranian neonatal intensive care unit: Hospital epidemiology and risk factors

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    Background: Hospital-acquired infection is one of the main concerns in Neonatal Intensive Care Units (NICUs), leading to increased mortality, hospital stay, and costs. Objectives: This study aimed to investigate the risk factors of hospital-acquired infection in NICUs. Methods: A descriptive, cross-sectional, prospective study was conducted in the NICU of Ali Asghar Children Hospital for one year. All admitted newborns were sampled on a simple basis. The criteria for the diagnosis of hospital-acquired infection were based on the definitions of the CDC and the NNIS system. Risk factors such as days of fully catheters usage, nurse-to-patient ratio, history of surgery, prematurity, and mechanical ventilation were considered as variables. The data collection tools consisted of a patient information questionnaire, the monthly report of the hospital infection control committee based on the NNIS system, a daily schedule of all risk factors for each infant, and the monthly nurse-to-patient ratio in the NICU. The STATA software was used for data analysis. Results: In our study, 654 newborns were enrolled. The rate of hospital-acquired infections was 13.5. Moreover, 80.7 of the cases exhibited sepsis (72.7 diagnosed based on clinical findings and 8 based on positive blood culture). Statistical analysis showed 9 pneumonia cases, 8 surgical site infection cases, and 2.3 urinary tract infection cases. The average time to the occurrence of hospital-acquired infection was 13.5 days after admission. All risk factors were significantly higher in the infected group than in the control group (P = 0.0001). Furthermore, surgical interventions were significantly more in the infected group than in the non-infected group (34.1 vs. 6.7, respectively, P = 0.0001). The prevalence rates in different weight ranges (less than 1000 g, 1001 to 1500 g, 1501 to 2500, and above 2501 g) were 2.6, 6.9, 21.4, and 69.1, respectively, in the infected group, which were significantly different from those of the non-infected group (P = 0.0001). The most common etiologic microorganism was Acinetobacter baumannii. Conclusions: Factors such as surgery, the presence of a central venous catheter, and the increased length of hospital stay significantly increased the hospital-acquired infections. Reducing invasive procedures, maintenance of full catheters, and providing optimal nursing care can help control hospital-acquired infections. © 2020, Author(s)

    A hierarchical model for the cash transfer system design problem

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    This paper presents a hierarchical model that incorporates strategic, tactical, and operational decisions of cash transfer management system of a bank. The aim of the model is to decide on the location of cash management centers, the number and routes of vehicles, and the cash inventory management policies to minimize the cost of owning and operating a cash transfer system while maintaining a pre-defined service level. Owing to the difficulty of finding optimal decisions in such integrated models, an iterative solution approach is proposed in which strategic, tactical, and operational problems are solved separately via a feedback mechanism. Numerical results show that such an approach is quite effective in reaching at greatly improved solutions with just a few iterations, making it a very promising approach for similar models

    Apixaban for Primary Prevention of Venous Thromboembolism in Patients With Multiple Myeloma Receiving Immunomodulatory Therapy

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    Immunomodulatory drugs (IMiDs), including thalidomide, lenalidomide, and pomalidomide, have improved survival of patients with multiple myeloma (MM). However, these therapies are associated with an increased risk of venous thromboembolism (VTE). Apixaban has been approved for treatment of acute VTE and for risk reduction of recurrent VTE following initial therapy. In this phase IV single-arm study (NCT02958969), we aim to prospectively evaluate the safety and efficacy of apixaban for primary prevention of VTE in patients with MM. The primary efficacy objective of this trial is to determine the rate of symptomatic VTE, including deep vein thrombosis (DVT) and pulmonary embolism (PE), over 6 months. The primary safety objective is to determine the rate of major bleeding in MM patients receiving apixaban prophylaxis. If proven safe and effective, apixaban will emerge as a promising option for oral VTE prophylaxis in MM patients
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