Forme chronique d’une maladie des éleveurs d’oiseaux: à propos d’une observation

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Optimization of Passive and Hybrid Mode-locked Figure Eight Laser

In pulsed fiber laser using Q-switching or mode locking techniques, the choice of the different components and the management of linear and non linear parameters of the cavity, play a paramount role in the generation of stable ultra short pulses with high peak powers and low widths. In this paper, we focus on the operating process of mode locked fiber lasers especially passively and hybrid type Eight Fiber Lasers (8FLs). By modeling the light propagation within the two cavities, we describe the whole operating process of ultra short pulses generation. The interaction between the mode locking mechanism and nonlinear effects in fiber laser is also illustrated. We demonstrate enhancing non linear effects do not lead necessarily to better results. It depends on the type of mode locking techniques used. The highest and narrowest output pulses are obtained for specific values of the non linear parameters and the mean dispersion of the cavity

Hysteresis phenomenon and multistability in figure-of-eight microstructured fiber laser

We report a theoretical investigation of multi-pulse emission of a microstructured figure-ofeight fiber laser operating in passive mode-locking. The proposed laser is mode locked by the nonlinear amplifying loop mirror (NALM). We study, in this paper, the hysteresis dependence and the number of pulses in steady state as a function of both the small signal gain and the nonlinear coefficient of microstructured fiber. The numerical simulation confirms that the pulse splitting is a consequence of the energy quantization in anomalous dispersion. Moreover, our results suggest that the hysteresis phenomenon is an intrinsic feature of the mode-locked fiber lasers independently of the exact mode-locking mechanism. Finally, we identify that the nonlinear coefficient of microstructured fiber plays a key role in the formation of multi-soliton

Experimental optimization of dissipative soliton resonance square pulses in all anomalous passively mode-locked fiber laser

We investigate experimentally the operational boundaries of dissipative soliton resonance in a double-clad Er:Yb co-doped dual amplifier passively mode-locked figure-of-eight fiber laser. While mode-locking with a nonlinear amplifying loop mirror, we present an exhaustive series of experiments in order to optimize the pulse energy and pulse width tunability. In addition to the pumping power of the amplifiers, several key experimental parameters have been identified such as the net cavity dispersion, the coupling ratio between the two loops of the cavity and the exact position of the long fiber coils. Under optimized conditions, the laser delivers square pulses with an energy varying between 8.5 and 10.1 μJ while the pulse width ranges from 84-416 ns

Carcinome épidermoïde Primitif de la Prostate: A propos d’un cas et revue de la littérature

Le cancer de la prostate est la tumeur maligne la plus fréquente chez l’homme. La grande majorité des tumeurs de la prostate est représentée par l’adénocarcinome prostatique (jusqu’à 95%). Le carcinome épidermoïde primitif est très rare et ne représente que 0,5% à 1% des carcinomes prostatiques. Jusqu’à 2014 seulement 24 cas ont été décrits dans la littérature. Nous rapportons un nouveau cas de carcinome épidermoide primitif de la prostate chez un jeune âgé de 48 ans diagnostiqué à un stade métastatique. Malgré une chimiothérapie à base de Cisplatine et Métoxantrone, le décès est survenu 2 mois après le diagnostic. A travers cette observation et une revue de la littérature, nous discutons les différents aspects cliniques, histologiques, thérapeutiques et pronostiques de cette tumeur.Mots clés: prostate; carcinome épidermoïde; histologie; métastases; traitement multimodalEnglish Title: Primary squamous cell carcinoma of the prostate: a case report and review of literatureEnglish AbstractProstate cancer is the most frequent malignant cancer in men, with the majority (nearly 95%) of prostate cancers being adenocarcinomas. Primary squamous cell carcinoma of the prostate is rare, representing only 0.5% to 1% of all prostatic carcinomas. Till 2014, only 24 cases have been published in the literature. We report a new case of primary squamous cell carcinoma of the prostate occurring in a young 48-years-old man and diagnosed at a metastatic stage. Despite of the chemotherapy based on Cisplatine and Méitoxantrone, death occurred two months after the diagnosis. Based on this observation and referring to literature review, we discuss the various clinical, histological, therapeutic and prognostic features of this rare tumour.Keywords: prostate; squamous cell carcinoma; histology; metastases; multimodal treatmen

Control of the square pulse properties in figure-of-eight microstructured fiber laser

We numerically analyze the square pulse emission from a passively mode-locked figure-of-eight microstructured optical fiber laser. Numerical simulations demonstrate that the high nonlinearity of the microstructured fiber plays a key role in the output pulse duration. A dual-stage erbium-doped fiber amplifier has been used in the cavity. The first amplifier, localized in the nonlinear amplifying loop mirror, allows control of the pulse width, while the second amplifier in the unidirectional ring allows variation of the amplitude without affecting the pulse width. Our results give some physical insight to the square pulse formation and the generation of high-energy pulses. Our numerical model provides a general approach to control the properties of a square pulse, and hence could be of great importance for the design of practical high-energy fiber laser systems

Widely tunable, narrow line width and low optical noise continuous-wave all fiber Er:Yb co-doped double-clad ring laser

In this paper, we report a widely tunable, narrow linewidth, low noise continuous-wave double-clad Er:Yb doped fiber ring laser. Tunability is demonstrated in wide range spanning from 1520 to almost 1620 nm covering the C and L spectral bands. The cavity design is optimized in order to achieve the largest tuning range with very high optical signal-to-noise ratio (SNR). The output coupling ratio greatly influences the tuning range of the laser while the position of the spectral filter determines the SNR. The obtained laser exhibits a tuning range over 98 nm with a nearly constant SNR of about 58.5 dB

10 μJ dissipative soliton resonance square pulse in a dual amplifier figure-of-eight double-clad Er:Yb mode-locked fiber laser

We demonstrate experimentally a double-clad Er:Yb co-doped dual amplifier passive mode-locked figure-of-eight fiber laser that generates high energy, width, and amplitude tunable dissipative soliton resonance square pulses. In our laser system, each loop contains an amplifier that controls a characteristic of the output pulse. The amplitude and width of the output beam can be controlled continuously but, dependently, according to the pump power of each amplifier. The pulse width can be tuned in a range of almost 360 ns while the peak power varies from 8 to 120 W. On maximum possible pumping from both sides without having a pulse break, we report square pulses with 10 μJ energy per pulse with a signal-to-noise ratio of 60 dB

Generation of high energy square-wave pulses in all anomalous dispersion Er:Yb passive mode locked fiber ring laser

We have experimentally demonstrated square pulses emission from a co-doped Er:Yb double-clad fiber laser operating in anomalous dispersion DSR regime using the nonlinear polarization evolution technique. Stable mode-locked pulses have a repetition rate of 373 kHz with 2.27 µJ energy per pulse under a pumping power of 30 W in cavity. With the increase of pump power, both the duration and the energy of the output square pulses broaden. The experimental results demonstrate that the passively mode-locked fiber laser operating in the anomalous regime can also realize a high-energy pulse, which is different from the conventional low-energy soliton pulse

Systemic sclerosis in a patient with pityriasis rubra pilaris

Pityriasis rubra pilaris (PRP) is a rare, chronic erythematous squamous disorder of unknown etiology. It has been found in association with several autoimmune diseases, including thyroiditis, myositis, myasthenia gravis and vitiligo. Herein we report a case of systemic sclerosis in a patient with classic adult pityriasis rubra pilaris. A 38 year old woman with classic adult type 1 pityriasis rubra pilaris (PRP) developed progressive skin thickening of the trunk, face, upper and lower extremities after 2 years of PRP treatment with topical emollients and steroids. Clinical examination and immunological findings were consistent with SSc. Co-existence of these two rare conditions is documented for the first time