Saint Francis University

About: Saint Francis University is a education organization based out in Loretto, Pennsylvania, United States. It is known for research contribution in the topics: Population & Osteoblast. The organization has 1694 authors who have published 2038 publications receiving 87149 citations.

Pathophysiology of Takotsubo Syndrome

Abstract: Transient left ventricular (LV) apical ballooning syndrome, Takotsubo cardiomyopathy, Takotsubo syndrome (TTS), broken heart syndrome, ampulla cardiomyopathy, or stress-induced cardiomyopathy are interchangeable terms and have all been applied to define a syndrome characterized by transient left ventricular systolic and diastolic dysfunction, electrocardiographic features and myocardial enzyme elevation similar to the acute myocardial infarction but in the absence of obstructive epicardial coronary artery disease. First described in Japan in the 1990s, the syndrome has gained worldwide attention within the scientific community in the past few decades. The disease manifests predominantly in postmenopausal females in the presence of stressful triggers such as severe physical or emotional stress, natural disasters such as earthquakes, unexpected death of relatives, acute medical illnesses, etc. Initially thought to be a benign condition, recent reports have demonstrated that TTS may be associated with severe complications and mortality similar to acute coronary syndrome. Concerted efforts have been made to define various pathophysiologic aspects of TTS; however, the precise etiologic understanding remains unclear. Some of the mechanisms proposed for the development of Takotsubo syndrome include elevated levels of circulating plasma catecholamines and their metabolites, microvascular dysfunction, inflammation, estrogen deficiency, spasm of the epicardial coronary vessels, and aborted myocardial infarction. Herein, we define each mechanism in further detail.The typical patient will present with chest pain, ECG showing ST-segment elevation, and increased troponin. However, when patients undergo cardiac catheterization, the left ventricle has apical ballooning and no evidence of coronary artery disease. The shape of the left ventricle during systole appears like an 'octopus pot.The modified Mayo Clinic criteria are used to make the diagnosis of Takotsubo cardiomyopathy and include the following: Absence of coronary artery disease on angiography Transient dyskinesis, hypokinesis, or akinesis of the left ventricle midsegments with or without apical involvement ECG evidence of ST-segment elevation and/or T wave inversion Modest elevation of troponin levels Absence of myocarditis or pheochromocytoma The exact number of people with the disorder remains unknown because not all patients undergo angiography following chest pain. The majority of patients are Asians or Whites and present with symptoms in the 6th decade of life. Close to 90% of cases have been reported in postmenopausal females.

Assembly of Gold Nanowires on Gold Nanostripe Arrays: Simulation and Experiment

Abstract: Nanowires (NWs) have a large aspect ratio and large available surface area, which have made them a potential platform for applications in biosensors as well as electronic/optic and power storage devices. However, the realization of many of these applications requires the wires to be positioned and oriented through an assembly process. Hence, it is essential to develop assembly strategies and techniques to achieve a variety of desired structures. In this work, we explored NW assembly using a patterned NW–substrate interaction. Experimentally, silica-coated Au nanowires (diameter of 340 nm, lengths of 2.4 and 4.4 μm, 30 nm SiO₂ shell) are allowed to self-assemble onto microfabricated Au features that create a series of “stripes” on a glass substrate (feature height of 50–200 nm; widths of 2.4, 4.5, and 4.8 μm). We observe a rich variety of patterns, with NWs concentrated atop the Au features and oriented perpendicular and diagonal to the stripe axes. We develop a model of this system by considering the relevant van der Waals and electrostatic interactions among NWs and between the NWs and stripes. Monte Carlo simulations of the assembly were performed based on this model, and good agreement with the experiment was achieved. An interesting finding from this work is that extra repulsion at the NW ends plays an important role in determining whether NWs order with their long axes parallel or perpendicular to the Au stripe axis. The simplicity of our approach makes this platform a promising way to achieve more elaborate nanoparticle assemblies in the future.

Emergy and Carbon Footprint Analysis of the Construction of Passive and Active Treatment Systems for Net Alkaline Mine Drainage

Abstract: Multi-criteria sustainability assessments were completed for the construction of a net-alkaline mine drainage passive treatment system (PTS) in northeastern Oklahoma to compare resource use and greenhouse gas emissions with a hypothetical active treatment system (ATS) alternative. Emergy analysis, an environmental accounting method assessing resource use, and carbon footprint analysis, a tool to evaluate greenhouse gas emissions, were completed for the construction of both systems. Assessing sustainability using multiple criteria is important in evaluating systems on the basis of resource use and environmental impact. Construction of the hypothetical ATS required seven times more emergy purchased from the economy and emitted three times more carbon dioxide equivalents than construction of the PTS. Concrete was the largest factor in both the emergy analysis (ATS and PTS) and carbon footprint (ATS only). Diesel fuel was the largest factor in the carbon footprint of PTS construction. This multi-criteria sustainability assessment shows that a hypothetical ATS alternative to the PTS would have used more resources and emitted more greenhouse gases during construction.