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J Abdallah

Publications and source records attributed to J Abdallah.

11 recordsLinked to original sources
PubMed2006

Spectroscopic characterization of an ultrashort-pulse-laser-driven Ar cluster target incorporating both Boltzmann and particle-in-cell models.

A model that solves simultaneously both the electron and atomic kinetics was used to generate a synthetic He alpha and satellite x-ray spectra to characterize a high intensity ultrashort laser driven Ar cluster target experiment. In particular, level populations were obtained from a detailed collisional-radiative model where collisional rates were computed from a time varying electron distribution function obtained from the solution of the zero-dimensional Boltzmann equation. In addition, a particle-in-cell simulation was used to model the laser interaction with the cluster target and provided the initial electron energy distribution function (EEDF) for the Boltzmann solver. This study suggests that a high density average, high, of 3.2 x 10(20) cm(-3) was held by the system for a time, delta tau, of 5.7 ps, and during this time the plasma was in a highly nonequilibrium state in both the EEDF and the ion level populations.

Journal Article↗
PubMed2002

Spatially resolved x-ray spectroscopy investigation of femtosecond laser irradiated Ar clusters.

High temperature plasmas have been created by irradiating Ar clusters with high intensity 60-fs laser pulses. Detailed spectroscopic analysis of spatially resolved, high resolution x-ray data near the He(alpha) line of Ar is consistent with a two-temperature collisional-radiative model incorporating the effects of highly energetic electrons. The results of the spectral analysis are compared with a theoretical hydrodynamic model of cluster production, as well as interferometric data. The plasma parameters are notably uniform over one Rayleigh length (600 microm).

Journal Article↗
PubMed1992

[Selective laryngeal re-innervations in the dog by nervous microsutures of branches of the recurrent laryngeal nerve].

INTRODUCTION: This work has been carried out to investigate in an animal model, the possibility of surgical selective reinnervation of the larynx following destruction of the laryngeal branch of the vagus nerve. MATERIAL AND METHODS: In ten dogs, on the right side of the neck only, the recurrent laryngeal nerve was identified, cut and section of the nerve removed. Following this the hemi-larynx on the operated side was reinnervated in the following manner. Using a microsurgical suture (described in the text) the motor nerves from extra-laryngeal muscles were anastomosed onto the nerves supplying the intrinsic abductors and adductors of the larynx. The nerve to sterno-thyroid was anastomosed onto the nerve supplying the posterior crico-arytenoid muscle (vocal cord abductor). Similarly the nerve supplying thyrohyoid was anastomosed onto the cut distal end of the adductor division of the recurrent laryngeal nerve. Clinical, electromyographical and histological evaluations have been used to prove the reinnervation. RESULTS: In the nine surviving animals successful re-innervations, as defined by the return of normal function, has been achieved for posterior crico-arytenoid and 7 adductor muscles. CONCLUSION: This study has demonstrated the feasibility of laryngeal reinnervation after surgical section of the recurrent laryngeal nerve, and give some cause for optimism for its ultimate application in man.

Anastomosis, Surgical↗
PubMed1988

Serum thymulin in human zinc deficiency.

The activity of thymulin (a thymic hormone) is dependent on the presence of zinc in the molecule. We assayed serum thymulin activity in three models of mildly zinc-deficient (ZD) human subjects before and after zinc supplementation: (a) two human volunteers in whom a specific and mild zinc deficiency was induced by dietary means; (b) six mildly ZD adult sickle cell anemia (SCA) subjects; and (c) six mildly ZD adult non-SCA subjects. Their plasma zinc levels were normal and they showed no overt clinical manifestations of zinc deficiency. The diagnosis of mild zinc deficiency was based on the assay of zinc in lymphocytes, granulocytes, and platelets. Serum thymulin activity was decreased as a result of mild zinc deficiency and was corrected by in vivo and in vitro zinc supplementation, suggesting that this parameter was a sensitive indicator of zinc deficiency in humans. An increase in T101-, sIg-cells, decrease in T4+/T8+ ratio, and decreased IL 2 activity were observed in the experimental human model during the zinc depletion phase, all of which were corrected after repletion with zinc. Similar changes in lymphocyte subpopulation, correctable with zinc supplementation, were also observed in mildly ZD SCA subjects. Inasmuch as thymulin is known to induce intra- and extrathymic T cell differentiation, our studies provide a possible mechanism for the role of zinc on T cell functions.

Adolescent↗