80 research outputs found

    Hyperbolic metamaterial interfaces: Hawking radiation from Rindler horizons and the "end of time"

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    Extraordinary rays in a hyperbolic metamaterial behave as particle world lines in a three dimensional (2+1) Minkowski spacetime. We analyze electromagnetic field behavior at the boundaries of this effective spacetime depending on the boundary orientation. If the boundary is perpendicular to the space-like direction in the metamaterial, an effective Rindler horizon may be observed which produces Hawking radiation. On the other hand, if the boundary is perpendicular to the time-like direction an unusual physics situation is created, which can be called "the end of time". It appears that in the lossless approximation electromagnetic field diverges at the interface in both situations. Experimental observations of the "end of time" using plasmonic metamaterials confirm this conclusion.Comment: 21 pages, 4 figure

    Experimental Modeling of Cosmological Inflation with Metamaterials

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    Recently we demonstrated that mapping of monochromatic extraordinary light distribution in a hyperbolic metamaterial along some spatial direction may model the flow of time and create an experimental toy model of the big bang. Here we extend this model to emulate cosmological inflation. This idea is illustrated in experiments performed with two-dimensional plasmonic hyperbolic metamaterials. Spatial dispersion which is always present in hyperbolic metamaterials results in scale-dependent (fractal) structure of the inflationary "metamaterial spacetime". This feature of our model replicates hypothesized fractal structure of the real observable universe.Comment: 17 pages, 3 figures. This version is accepted for publication in Physics Letters

    APF, HB-EGF, and EGF biomarkers in patients with ulcerative vs. non-ulcerative interstitial cystitis

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    BACKGROUND: Interstitial cystitis (IC) is a chronic bladder disorder, with symptoms including pelvic and or perineal pain, urinary frequency, and urgency. The etiology of IC is unknown, but sensitive and specific biomarkers have been described, including antiproliferative factor (APF), heparin-binding epidermal growth factor-like growth factor (HB-EGF), and epidermal growth factor (EGF). However, the relative sensitivity of these biomarkers in ulcerative vs. nonulcerative IC is unknown, and these markers have yet to be validated in another laboratory. We therefore measured these markers in urine from patients with or without Hunner's ulcer, as well as normal controls, patients with bladder cancer, and patients with bacterial cystitis, at the First Hospital of China Medical University. METHODS: Urine specimens were collected from two groups of Chinese IC patients (38 IC patients with Hunner's ulcers, 26 IC patients without Hunner's ulcers), 30 normal controls, 10 bacterial cystitis patients and 10 bladder cancer patients. APF activity was determined by measuring (3)H-thymidine incorporation in vitro, and HB-EGF and EGF levels were determined by ELISA. RESULTS: APF activity (inhibition of thymidine incorporation) was significantly greater in all IC patient urine specimens than in normal control specimens or in specimens from patients with bacterial cystitis or bladder cancer (p < 0.0001 for each comparison). Urine HB-EGF levels were also significantly lower and EGF levels significantly higher in both groups of IC patients than in the three control groups (p < 0.0001 for each comparison). Although APF and HB-EGF levels were similar in ulcerative and nonulcerative IC patients, EGF levels were significantly higher in IC patients with vs. without ulcers (p < 0.004). CONCLUSION: These findings indicate that APF, HB-EGF and EGF are good biomarkers for both ulcerative and nonulcerative IC and validate their measurement as biomarkers for IC in Chinese patients

    The effect of nitric oxide on the pressure of the acutely obstructed ureter

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    Acute ureteral obstruction leads to changes in pressure inside the ureter, interrupting ureter function. The aim of our study is to explore the relationship between nitric oxide (NO) concentration and pressure in the ureter and to observe the effects of nitric oxide on the revival of renal function. We created the animal models by embedding balloons in the lower ureters of anesthetized dogs and expanding them to simulate acute ureteral obstruction. First, the test animals were pre-treated intravenously with different doses of L-NAME (non-selective nitric oxide synthase inhibitor) to inhibit nitric oxide synthase (NOS), and 10 min later, each subject was administered an intravenous dose of isoproterenol (10 μg/kg). We measured ureter pressure (UP), total and peak concentrations of NO (using an NO monitor, model inNO-T) in ureteral urine, and the volume of the urine (UFV) leaking from the balloon edge. After a certain amount of time had elapsed, it became clear that the dose of L-NAME was inversely related to the total and peak concentrations of NO, the rate of change in UP, and the volume of urine produced. We conclude that L-NAME prevents the NOS from inhibiting the release of NO, then inhibits the effect of isoproterenol reducing the pressure of the acute obstructive ureter. Inversely, we think that NO can reduce the pressure of the acute obstructive ureter and make the obstructive ureter recanalization. And when more the concentration of nitric oxide, the more the pressure will be reduced, and more urine will be collected

    Hyperbolic metamaterial interfaces: Hawking radiation from Rindler horizons and spacetime signature transitions

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    Extraordinary rays in a hyperbolic metamaterial behave as particle world lines in a three-dimensional (2 + 1) Minkowski spacetime. We analyze electromagnetic field behavior at the boundaries of this effective spacetime depending on the boundary orientation. If the boundary is perpendicular to the spacelike direction in the metamaterial, an effective Rindler horizon may be observed, which produces Hawking radiation. On the other hand, if the boundary is perpendicular to the timelike direction, the system undergoes a phase transition to a state with a different nature of the spacetime, with nonintegrable field divergence at the transformation point. Experimental observations of the transition using plasmonic metamaterials confirm this conclusion
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