206 research outputs found

    Origins of the coronary arteries and their significance

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    OBJECTIVE: To describe the normal and variant anatomy of the coronary artery ostia in Indian subjects. INTRODUCTION: Anomalous coronary origins may cause potentially dangerous symptoms, and even sudden death during strenuous activity. A cadaveric study in an unsuspected population provides a basis for understanding the normal variants, which may facilitate determination of the prevalence of anomalies and evaluation of the value of screening for such anomalies. METHODS: One hundred and five heart specimens were dissected. The number of ostia and their positions within the respective sinuses were observed. Vertical and circumferential deviations of the ostia were observed. The heights of the cusps and the ostia from the bottom of the sinus were measured. RESULTS: No openings were present in the pulmonary artery or the non-coronary sinus. The number of openings in the aortic sinuses varied from 2-5 in the present series; multiple ostia were mostly seen in the anterior sinus. The majority of the ostia lay below the sinutubular ridge (89%) and at or above the level of the upper margin of the cusps (84%). Left ostial openings were mainly centrally located (80%), whereas the right coronary ostia were often shifted towards the right posterior aortic sinus (59%). DISCUSSION: The preferential location of the ostia was within the sinus and above the cusps, but below the sinutubular ridge. On occasion, normal variants like multiple ostia, vertical or circumferential shift in the position, and slit-like ostia may create confusion in interpreting the images and pose a difficulty during procedures like angiography, angioplasty, and coronary artery bypass grafting

    Macro-AFM model

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    An Atomic Force Microscope (AFM) is an important tool in modern nanoscience, capable of producing surface maps at resolutions below 1 nanometer, which is impossible for other methods. Despite AFM\u27s often use, it is often difficult for students to understand their work because all measurement processes take place at micro- and nano-scale. The goal of this project is to create a macro scale model, which will serve as an educational tool to introduce the principles behind AFM to undergraduate and high school students. Currently, a fully automatic microprocessor-controlled surface scanning block has been built and successfully tested with a scan area of ca. one square foot. Continued work includes designing and building of a topography measurement block that will work on the same principle as a real AFM does at nano-level. We expect that macro AFM building an image using AFM techniques will empower instructors to show the concepts, and to spark interest of potential students in Bioengineering

    NIR camera for early detection of diabetic ulcers

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    The purpose of this Creative Inquiry is to test whether near-infrared (NIR) imaging devices can detect areas of skin at risk for ulceration in diabetic patients. Venous blood accumulation, or high levels of deoxygenated blood within a tissue, can indicate poor blood circulation and increased risk of ulceration. Here we propose to detect venous blood in tissues using differences in optical spectra of oxygenated vs. deoxygenated blood in NIR region. We previously designed and built a prototype scanner with three integrated NIR light sources that is being tested at MUSC. Our current work is focused on testing of improved NIR illumination systems and improved NIR imaging device, and our second prototype that uses a more sensitive Raspberry Pi-controlled camera and advanced NIR light sources will provide significantly improved image quality. Upon success, the ultimate goal of this project is to manufacture a cheap, portable NIR camera for skin self-monitoring by diabetic patients

    Linearized MFL Model for Embedded Flaw Detection in Rails

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    Numerical models simulating magnetic flux leakage (MFL) phenomenon in ferromagnetic materials are nonlinear in nature and hence require excessive computational effort. This paper describes an approach for developing an equivalent linear model (ELM) where the ferromagnetic region is appropriately partitioned into different domains with each domain being assigned a constant permeability value depending on the magnetization level and the flaw size. The nonlinear behavior of the multi-layered object is then modeled using a linearized MFL model. The model is first validated and then applied to the flaw detection problem in a rail geometry.</p

    Calibration Of The Johnson–Cook Model At High Temperatures For An Ultra-High Strength CrNiMoV Steel

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    This paper presents a study on the thermo-mechanical behavior of an ultra-high strength CrNiMoV steel at high temperatures and medium strain rates through hot tensile tests. The material was examined in two conditions: as-cast/heat-treated (AC/HT) and as-rolled (AR). Tensile tests were conducted at temperatures of 800,900,1000,1100, and 1200°C, and strain rates of 0.1,1, and 10s−1. Inclusion and porosity analysis was also performed on the tensile specimens. The results revealed that the flow stress decreased by approximately 70% on average from 800°C to 1200°C, while increasing by approximately 32% on average from 0.1s−1 to 10s−1 in strain rate. The elongation exhibited an increase from 16.5% at 800°C to 33% at 1200°C. However, the ductility transition was slower than expected, particularly for the AC/HT conditions. The AC/HT samples exhibited higher levels of inclusions and porosity compared to the AR samples, with porosity significantly affecting the elongation to failure and ultimate tensile strength (UTS) at a strain rate of 1s−1. Furthermore, calibrated Johnson–Cook parameters were reported and compared, demonstrating excellent agreement between predicted and experimental values with less than 20% variation. The calibrated Johnson–Cook model can be effectively employed for modeling purposes within the studied temperature range, and its application can even be extrapolated for higher strain rates

    Applications of Hilbert Module Approach to Multivariable Operator Theory

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    A commuting nn-tuple (T1,…,Tn)(T_1, \ldots, T_n) of bounded linear operators on a Hilbert space \clh associate a Hilbert module H\mathcal{H} over C[z1,…,zn]\mathbb{C}[z_1, \ldots, z_n] in the following sense: C[z1,…,zn]×H→H,(p,h)↦p(T1,…,Tn)h,\mathbb{C}[z_1, \ldots, z_n] \times \mathcal{H} \rightarrow \mathcal{H}, \quad \quad (p, h) \mapsto p(T_1, \ldots, T_n)h,where p∈C[z1,…,zn]p \in \mathbb{C}[z_1, \ldots, z_n] and h∈Hh \in \mathcal{H}. A companion survey provides an introduction to the theory of Hilbert modules and some (Hilbert) module point of view to multivariable operator theory. The purpose of this survey is to emphasize algebraic and geometric aspects of Hilbert module approach to operator theory and to survey several applications of the theory of Hilbert modules in multivariable operator theory. The topics which are studied include: generalized canonical models and Cowen-Douglas class, dilations and factorization of reproducing kernel Hilbert spaces, a class of simple submodules and quotient modules of the Hardy modules over polydisc, commutant lifting theorem, similarity and free Hilbert modules, left invertible multipliers, inner resolutions, essentially normal Hilbert modules, localizations of free resolutions and rigidity phenomenon. This article is a companion paper to "An Introduction to Hilbert Module Approach to Multivariable Operator Theory".Comment: 46 pages. This is a companion paper to arXiv:1308.6103. To appear in Handbook of Operator Theory, Springe

    International health and Hispanic culture

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    This research project focuses on the interrelations between health and culture in the Hispanic countries and their impact on individuals and communities. The research explores medical diseases and conditions, people\u27s traditions, beliefs, and perceptions related to concerns related to health issues, home remedies, behavior change, family and community, doctor-patient relationship, and social aspects of public health (ethnicity, gender, poverty). Students will have the opportunity to travel to the Dominican Republic with the researchers and participate in service learning activities to help Hispanic communities and collect data for this research project. CI students will lead the following research topics in the Dominican Republic: 1) self-medication, low-income population accessibility to medicines, and the governmental pharmacy system (Boticas Populares) (Caleb Addis); 2) domestic violence as a public health concern (Aliyah Anjarwalla); 3) how chronic diseases are promoted, prevented and controlled (Deepti Athavale); 4) hepatitis A as a public health concern (Thomas Cotton); 5) challenges/barriers of people with disabilities to access physical therapy services (Breci Davis) ; 6) cultural and socio-economic determinants of childhood obesity (Michelle Fuentes); 7)medical equipment maintenance at public health care settings: advantages and disadvantages of donated equipment (Hannah Haire); 8) challenges and opportunities for the implementation of the HIV Vertical Transmission Prevention Program (Ashley Jamison); and 9) a behavioral theory analysis of drug abuse (Katherine Orellana)

    Fludrocortisone-a treatment for tubulopathy post-paediatric renal transplantation : a national paediatric nephrology unit experience

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    Calcineurin inhibitors post-renal transplantation are recognized to cause tubulopathies in the form of hyponatremia, hyperkalemia, and acidosis. Sodium supplementation may be required, increasing medication burden and potentially resulting in poor compliance. Fludrocortisone has been beneficial in addressing tubulopathies in adult studies, with limited paediatric data available. A retrospective review of data from an electronic renal database from December 2014 to January 2016 was carried out. Forty-seven post-transplant patients were reviewed with 23 (49%) patients on sodium chloride or bicarbonate. Nine patients, aged 8.3 years (range 4.9-16.4), commenced fludrocortisone 22 months (range 1-80) after transplant and were followed up for 9 months (range 2-20). All patients stopped sodium bicarbonate; all had a reduction or no increase in total daily doses of sodium chloride. Potassium levels were significantly lower on fludrocortisone, 5.2 vs 4.5 mmol/L, P = .04. No difference was noted in renal function (eGFR 77.8 vs 81.7 mL/min/1.73 m2 , P = .45) and no significant increase in systolic blood pressure (z-scores 0.99 vs 0.85, P = .92). No side effects secondary to treatment with fludrocortisone were reported. A significant proportion of renal transplant patients were on sodium supplementation and fludrocortisone reduced sodium supplementation without significant effects on renal function or blood pressure. Fludrocortisone appears to be safe and effective for tubulopathies in children post-transplantation

    Operator theory and function theory in Drury-Arveson space and its quotients

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    The Drury-Arveson space Hd2H^2_d, also known as symmetric Fock space or the dd-shift space, is a Hilbert function space that has a natural dd-tuple of operators acting on it, which gives it the structure of a Hilbert module. This survey aims to introduce the Drury-Arveson space, to give a panoramic view of the main operator theoretic and function theoretic aspects of this space, and to describe the universal role that it plays in multivariable operator theory and in Pick interpolation theory.Comment: Final version (to appear in Handbook of Operator Theory); 42 page

    Test, Reliability and Functional Safety Trends for Automotive System-on-Chip

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    This paper encompasses three contributions by industry professionals and university researchers. The contributions describe different trends in automotive products, including both manufacturing test and run-time reliability strategies. The subjects considered in this session deal with critical factors, from optimizing the final test before shipment to market to in-field reliability during operative life
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