Annu Int Conf IEEE Eng Med Biol Soc
July 2020
The Thulium fiber laser (TFL) is being explored as a potential alternative to the gold standard Holmium:YAG laser for infrared laser ablation of kidney stones. Laser-induced vapor bubbles contribute to both the ablation mechanism and stone retropulsion. In this preliminary study, a biocompatible surfactant with concentrations of 1-5% was used to enhance the vapor bubble dimensions during the laser pulse.
View Article and Find Full Text PDFThis paper describes the application of a human color vision approach to infrared (IR) chemical sensing for the discrimination between multiple explosive materials deposited on aluminum substrates. This methodology classifies chemicals using the unique response of the chemical vibrational absorption bands to three broadband overlapping IR optical filters. For this effort, Fourier transform infrared (FT-IR) spectroscopy is first used to computationally examine the ability of the human color vision sensing approach to discriminate between three similar explosive materials, 1,3,5,-Trinitro-1,3,5-triazinane (RDX), 2,2-Bis[(nitrooxy)methyl]propane-1,3,-diyldinitrate (PETN), and 1,3,5,7-Tetranitro-1,3,5,7-tetrazocane (HMX).
View Article and Find Full Text PDFBACKGROUND A coronary artery-left ventricular fistula is an anomalous communication between the coronary arteries and the cardiac chambers and is a rare congenital coronary anomaly that is often small and asymptomatic. Takotsubo cardiomyopathy, on the other hand, is a syndrome characterized by transient regional systolic dysfunction of the left ventricle, mimicking myocardial infarction, but in the absence of angiographic evidence of obstructive coronary artery disease or acute plaque rupture. We present the case of an elderly woman who presented with Takotsubo cardiomyopathy and who was incidentally discovered to have an associated coronary artery-left ventricular fistula.
View Article and Find Full Text PDFBiomechanics of unobstructed locomotion consists of synchronized complex movements of the pelvis, torso, and lower limbs. These movement patterns become more complex as individuals encounter obstacles or negotiate uneven terrain. To date, limited research has explored how specifically the pelvis, torso, and lower limb segments relate to obstacle negotiation of varying sized objects combined with temporal constraints to perform the task.
View Article and Find Full Text PDFThe Thulium fiber laser (TFL) is being explored as an alternative to the Holmium : YAG laser for lithotripsy. TFL parameters differ in several fundamental ways from Holmium laser, including smaller fiber delivery, more strongly absorbed wavelength, low pulse energy/high pulse rate operation, and more uniform temporal pulse structure. High speed imaging of laser induced bubbles was performed at 105,000 frames per second and 10 μm spatial resolution to determine influence of these laser parameters on bubble formation and needle hydrophone data was also used to measure pressure transients.
View Article and Find Full Text PDFThe thulium fiber laser (TFL) is being explored as an alternative laser lithotripter to the standard holmium:yttrium-aluminum-garnet laser. The more uniform beam profile of the TFL enables higher power transmission through smaller fibers. In this study, a 100-μm core, 140-μm outer-diameter (OD) silica fiber with 5-mm length hollow steel tip was integrated with 1.
View Article and Find Full Text PDFLasers have been used in combination with applied cooling methods to preserve superficial skin layers (100's μm's) during cosmetic surgery. Preservation of a thicker tissue surface layer (millimeters) may also allow development of other noninvasive laser procedures. We are exploring noninvasive therapeutic laser applications in urology (e.
View Article and Find Full Text PDFBackground: The experimental Thulium fiber laser (TFL) is currently being studied as a potential alternative lithotripter to the clinical gold standard Holmium:YAG laser. Safety studies characterizing undesirable Holmium:YAG laser-induced damage to ureter tissue and stone baskets have been previously reported. Similarly, this study characterizes TFL induced ureter and stone basket damage.
View Article and Find Full Text PDFUsing a validated in vitro ureter model for laser lithotripsy, the performance of an experimental thulium fiber laser (TFL) was studied and compared to the clinical gold standard holmium:YAG laser. The holmium laser (λ = 2120 nm) was operated with standard parameters of 600 mJ, 350 μs, 6 Hz, and 270-μm-core optical fiber. The TFL (λ=1908 nm) was operated with 35 mJ, 500 μs, 150 to 500 Hz, and a 100-μm-core fiber.
View Article and Find Full Text PDFFeeding Wistar rats a high calorie "Western" diet (45% fat) for up to 48 weeks induces obesity and cardiac dysfunction, while a high fat diet (60% fat) induces obesity only. Here we investigated the molecular "footprints" of the two forms of diet-induced obesity in the heart. In rats fed Western diet for a long term, cardiac mRNA transcript levels of malic enzyme were decreased (-72%, P < 0.
View Article and Find Full Text PDFThe normal heart responds to changes in its metabolic milieu by changing relative oxidation rates of energy-providing substrates. We hypothesized that this flexibility is lost when genetically obese rats are fed a high-caloric, high-fat "Western" diet (WD). Male Zucker obese (ZO) and Zucker lean (ZL) rats were fed either control or WD composed of 10 kcal% and 45 kcal% fat, respectively, for 7 or 28 days.
View Article and Find Full Text PDFThe "lipotoxic footprint" of cardiac maladaptation in diet-induced obesity is poorly defined. We investigated how manipulation of dietary lipid and carbohydrate influenced potential lipotoxic species in the failing heart. In Wistar rats, contractile dysfunction develops at 48 weeks on a high-fat/high-carbohydrate "Western" diet, but not on low-fat/high-carbohydrate or high-fat diets.
View Article and Find Full Text PDFPrevious studies suggest that disease recurrence peaks at around 2 years in patients with early stage breast cancer (EBC), but provide no data regarding recurrence type. This retrospective analysis aimed to identify early recurrence types and risk factors in estrogen receptor-positive (ER+) EBC patients treated with adjuvant tamoxifen following breast cancer surgery. Postmenopausal women diagnosed with ER+ EBC from 1995 to 2004 were evaluated.
View Article and Find Full Text PDFObesity affects the cardiovascular system at many different levels, including the heart muscle itself. Clinical and experimental studies have shown an accumulation of triglycerides and other lipid species in cardiomyocytes. Analogous to hepatic steatosis, investigators have introduced the term “cardiac steatosis”.
View Article and Find Full Text PDFAn indirect fluorescence (FL) detection method via the reactivity of UV-photolyzed 2-phenylbenzimidazole-5-sulfonate (PBSA) has been developed for non-fluorescent aromatic compounds. At high pH with UV photolysis, PBSA in the excited state is known to be quenched by reaction with oxygen species and analyte compounds that are reactive toward these oxygen species produced during photolysis can lessen the loss of PBSA FL. After off-line photolysis of PBSA in the presence of various nitro-aromatic test compounds, the increase in PBSA FL is clearly evident.
View Article and Find Full Text PDFObesity and diabetes are associated with increased fatty acid availability in excess of muscle fatty acid oxidation capacity. This mismatch is implicated in the pathogenesis of cardiac contractile dysfunction and also in the development of skeletal-muscle insulin resistance. We tested the hypothesis that 'Western' and high fat diets differentially cause maladaptation of cardiac- and skeletal-muscle fatty acid oxidation, resulting in cardiac contractile dysfunction.
View Article and Find Full Text PDFThe Cdk7/cyclin H/ménage-à-trois 1 (MAT1) heterotrimer has proposed functions in transcription as the kinase component of basal transcription factor TFIIH and is activated in adult hearts by Gq-, calcineurin-, and biomechanical stress-dependent pathways for hypertrophic growth. Using cardiac-specific Cre, we have ablated MAT1 in myocardium. Despite reduced Cdk7 activity, MAT1-deficient hearts grew normally, but fatal heart failure ensued at 6-8 weeks.
View Article and Find Full Text PDFThe discovery of novel serological biomarkers is critical for improving disease diagnosis and monitoring treatment response. Proteomic analysis of model systems, such as isolated cells in culture and patient plasma and serum, represents the current state-of-the-art. Here, we coupled proteomics with isolated organ perfusion, which allows a disease state to be studied in a physiologic, yet controlled, environment.
View Article and Find Full Text PDFFrom the first stages of differentiation in the embryo to the end of life, energy substrate metabolism and function are inextricably linked features of the heart. The principle of energy substrate metabolism is simple. For a given developmental stage and for a given environment, the heart oxidizes the most efficient fuel on the path to ATP.
View Article and Find Full Text PDFIt is suggested that insulin resistance and metabolic maladaptation of the heart are causes of contractile dysfunction. We tested the hypothesis whether systemic PPARgamma activation, by changing the metabolic profile in a model of insulin resistance and type 2 diabetes (the ZDF rat) in vivo, improves contractile function of the heart in vitro. Male Zucker diabetic fatty (ZDF) and Zucker lean (ZL) rats, at 53-56 days of age, were treated with either GI-262570 (a nonthiazolidinedione PPARgamma agonist; A) or vehicle (V) for 1 wk.
View Article and Find Full Text PDFThe heart, like other organs, possesses an internal circadian clock. These clocks provide the selective advantage of anticipation, enabling the organ to prepare for a given stimulus, thereby optimizing the appropriate response. The heart in diabetes is associated with alterations in morphology, gene expression, metabolism and contractile performance.
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