The Experts below are selected from a list of 50514 Experts worldwide ranked by ideXlab platform
Shiquan Yang - One of the best experts on this subject based on the ideXlab platform.
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Evolution behavior of chirped tan-hyperbolic pulse through single mode Fiber in the simultaneous presence of Fiber Loss, dispersion and self-phase modulation
Telecommunication Systems, 2014Co-Authors: M. Yousaf Hamza, Noureen Akhtar, Nadeem Sarwar, Shiquan YangAbstract:We present the results of tan-h pulse propagation through single mode Fiber in dispersion dominant regime as well as in the simultaneous presence of Fiber Loss, group velocity dispersion and self-phase modulation. Both un-chirped/chirped cases have been considered. The pulse was propagated using split-step Fourier method based nonlinear Schrödinger equation. Results clearly show that in the absence of Fiber nonlinearity, the pulse goes on broadening with the propagated distance. However, in the presence of the Fiber nonlinearity, the pulse initially experiences compression and then undergoes broadening at a faster rate. As the value of sharpness parameter increases, the compression also increases. The results of compensation of group velocity dispersion using dispersion compensating Fiber considering the setups of pre-, post- and the combination of pre- and post-compensations are also presented. These investigations provide a detailed study and deeper insight about how Fiber responses to such type of optical pulses.
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TSP - Investigations of chirped tan-hyperbolic pulse propagation behavior in the presence of Fiber Loss, dispersion and self-phase modulation of single mode Fiber
2011 34th International Conference on Telecommunications and Signal Processing (TSP), 2011Co-Authors: M. Yousaf Hamza, Noureen Akhtar, Nadeem Sarwar, Shiquan YangAbstract:Results of tan-hyperbolic pulse propagation in dispersion dominant regime as well as in the simultaneous presence of Fiber Loss, dispersion and self-phase modulation in single mode Fiber are presented, both for initially un-chirped and chirped cases. Split-step Fourier model for nonlinear Schrodinger equation was used for this purpose. Results clearly show that in the presence of Fiber nonlinearity, by increasing the steepness parameter, initially the un-chirped pulse first undergoes compression and then it goes on broadening with the propagated distance. Results also show that for higher value of steepness parameter, if the value of initial chirp goes on decreasing, peak power also increase showing the compression of the pulse and then it decreases with the propagated distance in dispersion dominant regime. The inclusion of self-phase modulation further enhances these results. These investigations provide a deeper insight for the Fiber response to such type of optical pulses.
Vinita Singhgupta - One of the best experts on this subject based on the ideXlab platform.
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elamipretide reduces the burden for induction of apoptosis in skeletal muscle of dogs with chronic heart failure
Journal of the American College of Cardiology, 2019Co-Authors: Hani N. Sabbah, Ramesh C. Gupta, Kefei Zhang, Jiang Xu, Vinita SinghguptaAbstract:Exercise intolerance (Ex-Int) is a feature of heart failure (HF) and is attributed to skeletal muscle (SM) abnormalities including Fiber type composition, atrophy, Fiber Loss, and mitochondrial (MITO) dysfunction. MITO dysfunction can activate apoptosis by releasing cytochrome C (CYTO-C) into the
David J. Webb - One of the best experts on this subject based on the ideXlab platform.
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Stress Sensitivity Analysis of Optical Fiber Bragg Grating-Based Fabry–Pérot Interferometric Sensors
Journal of Lightwave Technology, 2017Co-Authors: Andreas Pospori, David J. WebbAbstract:A stress sensitivity analysis of optical Fiber-based Fabry-Perot (FP) sensors has been performed, taking into account the influence of Fiber Loss on the interferometric sensitivity. The sensitivity increases proportionally with the interferometric cavity length, but it decreases with the attenuation present along the optical path. In addition, Fibers constructed from materials with lower Young's modulus provide higher intrinsic stress sensitivity. In this study, three Fiber materials have been studied: fused silica, poly (methyl methacrylate) (PMMA), and cyclic transparent optical polymer (CYTOP), which have different Young's modulus and optical attenuation. In general, PMMA-based FPs are best for the shortest cavity lengths due to their lower Young's modulus, the performance of silica dominates for long cavities due to the lowest Fiber Loss and CYTOP is the best choice for medium length cavities. The boundaries between the three length regimes depend on the operating wavelength (which strongly influences the Fiber Loss) and the reflectivity of the mirrors forming the interferometer. Where the mirrors take the form of Fiber Bragg gratings, the grating length also impacts the system performance. The presented model can be used to identify which material offers the highest stress sensitivity when the physical and optical characteristics of a FP stress sensor have been predefined.
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stress sensitivity analysis of optical Fiber bragg grating based fabry perot interferometric sensors
Journal of Lightwave Technology, 2017Co-Authors: Andreas Pospori, David J. WebbAbstract:A stress sensitivity analysis of optical Fiber-based Fabry-Perot (FP) sensors has been performed, taking into account the influence of Fiber Loss on the interferometric sensitivity. The sensitivity increases proportionally with the interferometric cavity length, but it decreases with the attenuation present along the optical path. In addition, Fibers constructed from materials with lower Young's modulus provide higher intrinsic stress sensitivity. In this study, three Fiber materials have been studied: fused silica, poly (methyl methacrylate) (PMMA), and cyclic transparent optical polymer (CYTOP), which have different Young's modulus and optical attenuation. In general, PMMA-based FPs are best for the shortest cavity lengths due to their lower Young's modulus, the performance of silica dominates for long cavities due to the lowest Fiber Loss and CYTOP is the best choice for medium length cavities. The boundaries between the three length regimes depend on the operating wavelength (which strongly influences the Fiber Loss) and the reflectivity of the mirrors forming the interferometer. Where the mirrors take the form of Fiber Bragg gratings, the grating length also impacts the system performance. The presented model can be used to identify which material offers the highest stress sensitivity when the physical and optical characteristics of a FP stress sensor have been predefined.
Martijn R. Tannemaat - One of the best experts on this subject based on the ideXlab platform.
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Cibinetide Improves Corneal Nerve Fiber Abundance in Patients With Sarcoidosis-Associated Small Nerve Fiber Loss and Neuropathic Pain
Investigative Opthalmology & Visual Science, 2017Co-Authors: Daniel A. Culver, Maria Jeziorska, Albert Dahan, Ann Dunne, Monique Van Velzen, Martijn R. Tannemaat, Daiva Bajorunas, Leon Aarts, Jinny Tavee, Rita I KirkAbstract:Purpose Sarcoidosis frequently is complicated by small nerve Fiber Loss (SNFL), which can be quantified using corneal confocal microscopy (CCM). Prior studies suggest that the innate repair receptor agonist cibinetide reverses corneal nerve Loss. This phase 2b, 28-day, randomized trial of 64 subjects with sarcoid-associated SNFL and neuropathic pain assessed the effect of cibinetide on corneal nerve Fiber area (CNFA) and regenerating intraepidermal Fibers (GAP-43+) as surrogate endpoints for disease modification, pain severity, and functional capacity (6-minute walk test [6MWT]). Methods Cibinetide (1, 4, or 8 mg/day) was compared to placebo. The primary study endpoint was a change in CNFA at 28 days. Results The placebo-corrected mean change from baseline CNFA (μm2) at day 28 was 109 (95% confidence interval [CI], -429, 647), 697 (159, 1236; P = 0.012), and 431 (-130, 992) in the 1, 4, and 8 mg groups, respectively. Intraepidermal GAP-43+ Fibers increased in the 4 mg group (P = 0.035). Further, changes in CNFA correlated with changes in GAP-43+ (ρ = 0.575; P = 0.025) and 6MWT (ρ = 0.645; P = 0.009). Pain improved significantly in all groups, with subjects having moderate-severe pain reporting a clinically meaningful placebo-corrected decrease in pain intensity in the 4 mg group (P = 0.157). Conclusions Cibinetide significantly increased small nerve Fiber abundance in the cornea and skin, consistent with a disease modifying effect. The relationships between CNFA and other clinical measures of disease support its use as a surrogate endpoint to assess potential disease modifying therapies for neuropathy.
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ARA 290 Improves Symptoms in Patients with Sarcoidosis-Associated Small Nerve Fiber Loss and Increases Corneal Nerve Fiber Density
Molecular Medicine, 2013Co-Authors: Albert Dahan, Ann Dunne, Maarten Swartjes, P.l. Proto, Lara Heij, O.j.m. Vogels, Monique Van Velzen, Elise Sarton, Marieke Niesters, Martijn R. TannemaatAbstract:Small nerve Fiber Loss and damage (SNFLD) is a frequent complication of sarcoidosis that is associated with autonomic dysfunction and sensory abnormalities, including pain syndromes that severely degrade the quality of life. SNFLD is hypothesized to arise from the effects of immune dysregulation, an essential feature of sarcoidosis, on the peripheral and central nervous systems. Current therapy of sarcoidosis-associated SNFLD consists primarily of immune suppression and symptomatic treatment; however, this treatment is typically unsatisfactory. ARA 290 is a small peptide engineered to activate the innate repair receptor that antagonizes inflammatory processes and stimulates tissue repair. Here we show in a blinded, placebo-controlled trial that 28 d of daily subcutaneous administration of ARA 290 in a group of patients with documented SNFLD significantly improves neuropathic symptoms. In addition to improved patient-reported symptom-based outcomes, ARA 290 administration was also associated with a significant increase in corneal small nerve Fiber density, changes in cutaneous temperature sensitivity, and an increased exercise capacity as assessed by the 6-minute walk test. On the basis of these results and of prior studies, ARA 290 is a potential disease-modifying agent for treatment of sarcoidosis-associated SNFLD.
Bernd Kohler - One of the best experts on this subject based on the ideXlab platform.
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early detection of nerve Fiber Loss by corneal confocal microscopy and skin biopsy in recently diagnosed type 2 diabetes
Diabetes, 2014Co-Authors: Dan Ziegler, Nikolaos Papanas, Andrey Zhivov, Stephan Allgeier, Karsten Winter, Iris Ziegler, Jutta Bruggemann, Alexander Strom, Sabine Peschel, Bernd KohlerAbstract:We sought to determine whether early nerve damage may be detected by corneal confocal microscopy (CCM), skin biopsy, and neurophysiological tests in 86 recently diagnosed type 2 diabetic patients compared with 48 control subjects. CCM analysis using novel algorithms to reconstruct nerve Fiber images was performed for all Fibers and major nerve Fibers (MNF) only. Intraepidermal nerve Fiber density (IENFD) was assessed in skin specimens. Neurophysiological measures included nerve conduction studies (NCS), quantitative sensory testing (QST), and cardiovascular autonomic function tests (AFTs). Compared with control subjects, diabetic patients exhibited significantly reduced corneal nerve Fiber length (CNFL-MNF), Fiber density (CNFD-MNF), branch density (CNBD-MNF), connecting points (CNCP), IENFD, NCS, QST, and AFTs. CNFD-MNF and IENFD were reduced below the 2.5th percentile in 21% and 14% of the diabetic patients, respectively. However, the vast majority of patients with abnormal CNFD showed concomitantly normal IENFD and vice versa. In conclusion, CCM and skin biopsy both detect nerve Fiber Loss in recently diagnosed type 2 diabetes, but largely in different patients, suggesting a patchy manifestation pattern of small Fiber neuropathy. Concomitant NCS impairment points to an early parallel involvement of small and large Fibers, but the precise temporal sequence should be clarified in prospective studies.