Nearly chirp- and pedestal-free pulse compression in nonlinear fiber Bragg gratings

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Exact States in Waveguides With Periodically Modulated Nonlinearity

We introduce a one-dimensional model based on the nonlinear Schrodinger/Gross-Pitaevskii equation where the local nonlinearity is subject to spatially periodic modulation in terms of the Jacobi dn function, with three free parameters including the period, amplitude, and internal form-factor. An exact periodic solution is found for each set of parameters and, which is more important for physical realizations, we solve the inverse problem and predict the period and amplitude of the modulation that yields a particular exact spatially periodic state. Numerical stability analysis demonstrates that the periodic states become modulationally unstable for large periods, and regain stability in the limit of an infinite period, which corresponds to a bright soliton pinned to a localized nonlinearity-modulation pattern. Exact dark-bright soliton complex in a coupled system with a localized modulation structure is also briefly considered . The system can be realized in planar optical waveguides and cigar-shaped atomic Bose-Einstein condensates.Comment: EPL, in pres

Analytical method for designing grating compensated dispersion-managed soliton systems

This paper was published in Journal of Optical Society of America B and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.opticsinfobase.org/abstract.cfm?URI=JOSAB-21-4-706. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law. © 2004 The Optical Society.Peer reviewedPublisher PD

Generation of a train of ultrashort pulses using periodic waves in tapered photonic crystal fibres

Funding This work was supported by the Ministry of Education , Nigeria for financial support through the TETFUND scholarship 55 scheme; CSIR [grant number 03(1264)/12/EMR-II].Peer reviewedPostprin

Control of Long Pulse Pumped Supercontinuum Generation Using Weak Trigger Signal

This work was supported by National Natural Science Foundation of China under Grants 61675008, and Shenzhen Science and Technology Innovation Commission under Grant GJHZ20180411185015272.Peer reviewedPostprin

An analytical approach to integral resonant control of second-order systems

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Statistical Modelling of Photonic Crystal Fibre based Surface Plasmon Resonance Sensors Resonant Peak Wavelength for Tolerance Studies

Funding: This research received no external funding. Acknowledgments: The authors thank Dr. Alison Nordon for the useful discussion. Samuel Osifeso acknowledges the award of a PhD scholarship by Tertiary Education Trust Fund (TETFund). Suoda Chu acknowledges the award of a Postdoc fellowship by the Community for Analytical Measurement Science (CAMS).Peer reviewedPublisher PD

Designing a Biosensor Using a Photonic Quasi-Crystal Fiber with Fan-shaped Analyte Channel

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Oxidative status in feline pyometra

The oxidative status of the organism is dependent of the balance between oxidant reactants and antioxidant defenses. Oxidative stress develops when the oxidant reactants exceed the antioxidant defenses of the organism. The oxidative stress causes alterations in cellular metabolism and cellular damage. The antioxidant response of the organism can be assessed by determination of individual parameters such as total serum thiols (Thiol) and/or by determination of the total antioxidant capacity (TAC) of the organism. Parameters of oxidative status have proved to be useful biomarkers in several canine and feline diseases. Pyometra is considered one of the most important uterine diseases in cats. However, information about the oxidative status in queens with pyometra is lacking. Therefore, the main objectives of this study were to evaluate the oxidative status of feline pyometra through the determination of serum concentration of Thiol and TAC, and to evaluate the clinical evolution of these antioxidants in the post-ovariohysterectomy period. Serum concentrations of Thiol and TAC (determined by four different methodologies) were assessed in 17 queens with pyometra and in 13 healthy queens submitted to elective ovariohysterectomy (control group). Serum Thiol and TAC were also evaluated in six queens with pyometra at days two and 10 after surgery. Routine histopathology of the reproductive organs was performed in all animals, to confirm pyometra in the diseased queens, and to exclude uterine pathology in the control cats. At presentation, diseased queens presented significantly lower serum concentrations of Thiol and TAC than controls (P<0.001 in both cases). In the queens in which serial determinations of antioxidants were performed, serum Thiol and TAC were significantly higher at day 10 post-surgery than at presentation (P<0.05 in both cases). The results of the present study indicate that pyometra in queens is associated with presence of oxidative stress. Moreover, serum Thiol and TAC tended to evolve to physiologic values after surgery. Therefore, oxidative stress parameters could be useful in assessing the post-operative period in feline pyometra.O estado oxidativo do organismo depende do equilibrio entre os agentes oxidantes e os antioxidantes. O stresse oxidativo de senvolve-se quando os agentes oxidantes excedem a capacidade antioxidante do organismo. O stress oxidativo causa danos celulares, bem como alterações no seu metabolismo. A resposta antioxidante pode ser avaliada através da determinação de parâmetros individuais, tais como os tióis séricos, ou através da determinação da capacidade antioxidante total (TAC, do Inglês Total Antioxidant Capacity) do organismo. Diferentes parâmetros de avaliação do estado oxidativo do organismo provaram ser biomarcadores clinicamente úteis em diferentes doenças em cães e gatos. Contudo, existe falta de informação sobre o estado oxidativo em gatas com piómetra. Desta forma, os objetivos principais deste estudo foram avaliar o estado oxidativo em gatas diagnosticadas com piómetra, através da determinação dos níveis séricos de tióis e TAC (determinados através de quatro métodos diferentes: TEAC1, TEAC2, FRAP E CUPRAC), e avaliar a evolução clínica destes antioxidantes no período pós-ovariohisterectomia. As concentrações séricas de tióis e TAC foram determinadas em 17 gatas com piómetra (grupo em teste) e em 13 gatas saudáveis submetidas a ovariohisterectomia eletiva (grupo de controlo). Em seis gatas com piómetra foi possível efetuar o doseamento de tióis e TAC nos dias dois e 10 após a cirurgia. Foi realizada histopatologia dos órgãos reprodutores de todas as gatas incluídas no estudo, para comprovar a presença de piómetra nas gatas doentes, e para excluir doenças uterinas no grupo de controlo. No momento do diagnóstico, as gatas com piómetra apresentaram concentrações séricas de tióis e TAC significativamente inferiores às gatas do grupo de controlo (P<0,001 em ambos os casos). Nas gatas em que foi realizado um seguimento no período pós-cirurgia através de medições seriadas de antioxidantes, as concentrações de tióis e TAC apresentaram-se significativamente superiores no décimo dia pós-ovariohisterectomia que no dia do diagnóstico (P<0,05 em ambos os casos). Segundo os resultados obtidos neste estudo, em gatas a piómetra está associada ao desenvolvimento de stresse oxidativo. Para além disso, as concentrações séricas dos antioxidantes analisados tenderam a retomar os valores fisiológicos no período pós-ovariohisterectomia. Assim, estes parâmetros indicam utilidade clínica na monitorização do período pós cirúrgico em gatas com piómetra