275 research outputs found
Biosorption of Co (II) ions from aqueous solutions using selected local Luffa Cylindrica: Adsorption and characterization studies
The present study is concerned with the removal of Cobalt (II) from aqueous solution by adsorption onto low cost adsorbent. Luffa Cylindrica as adsorbent, (LC) was investigated in batch adsorption system. LC was characterized by Scanning Electron Microscopy (SEM) and Brunauer-Emmett-Teller (BET) surface area analyzer. The sorption of Co (II) ions by LC was subjected to equilibrium, thermodynamics and kinetic studies and was carried out by considering the effects of pH, effect of masse and particles size of the biosorbent, initial metal ions concentration, contact time and temperature. BET surface area of LC was 46.396 m2/g. The optimum conditions for maximum adsorption were attained at pH 6 and LC mass is 1.5 g with particle size is < 0.08 mm and contact time is 60 min. The pseudo-second-order rate equation described the Kinetic data well. The process is chemisorptive and controlled by the pseudo-second-order. Adsorption parameters were determined using both Langmuir and Freundlich isotherms, but the experimental data were better fitted to the Langmuir equation than to Freundlich equation, with correlation coefficients above 0.99 which indicates the adsorption is monolayer adsorption with maximum adsorption capacity for Co(II) was 2.53 mg/g
Reactivity of 3-hydroxy-3-methyl-2-butanone: Photolysis and \OH\ reaction kinetics
International audienceHydroxycarbonyl compounds are important secondary reaction products in the oxidation of Volatile Organic Compounds (VOCs) in the atmosphere. The atmospheric fate of these oxygenated \VOCs\ is however poorly understood, especially the relevance of the photolytic pathway. In this work, a combined investigation of the photolysis and temperature-dependent \OH\ radical reaction of 3-hydroxy-3-methyl-2-butanone (3H3M2B) is presented. A photolysis lifetime of about 4-5 days was estimated with a global quantum yield of 0.10. The \OH\ reaction rate coefficient follows the Arrhenius trend (298-356 K) and could be modelled through the following expression: k3H3M2B(T) = (5.12 ± 0.07) × 10−12 exp(−563 ± 119/T) in cm3 molecule−1 s−1. A 3H3M2B atmospheric lifetime of 15 days towards the \OH\ radical was evaluated. Our results showed that the photolysis pathway is the major degradation channel for 3H3M2B. Photolysis products were identified and quantified in the present work with a carbon balance of around 80% enabling a reaction mechanism to be proposed. The present work underlines the need for further studies on the atmospheric chemistry of oxygenated VOCs
Syringomatous carcinoma: Case report of a rare tumor entity
Syringomatous carcinoma is a rare cutaneous neoplasm, most frequently situated on the face and scalp and histologically characterised by aninfiltrative pattern of basaloid or squamous cells, a desmoplastic stromal reaction and keratin filled cysts. We report the case of a 76-year-oldwoman who presented an ulcerative interscapular lesion measuring 3x4cm. After resection, the histological examinations of the specimens haveidentified a basal cell carcinoma. However, a local recurrence was observed 18 months later; histopathological findings showed a syringomatouspattern and neoplastic epithelial cells arranged in interconnecting cords with microcystic areas. Nests, cords, and tubules of the tumour extendedinto the dermis and into the adjacent muscle. Sclerosis of stroma around the cords was present. Tumour cells were not connected to the epidermis. The immunohistochemical analysis showed positivity for anti-CK7, AE1/AE3 and negativity for anti CEA and anti CK20. These histological and immunohistochemical analyses were consistent with the diagnosis of syringomatous eccrine carcinoma. Syringomatous carcinoma is an extremely invasive tumor, locally destructive and slowly growing adnexal tumour, derived from eccrine sweat glands. It is often mistaken, both clinically and microscopically, for other benign and malignant entities. The tumour recurrence is high due to extensive perineural invasion, butregional or distant metastases are rare. The local aggressive nature of the tumour and the high recurrence rate may necessitate mutilating procedures. Optimal treatment consists of a complete microscopically controlled surgical excision with clear surgical margins. Key words: Syringomatous carcinoma, histopathology, immunohistochemistry, differential diagnosi
Surface Optical Waves at Air/Metal Interfaces: Surface Plasmon Polaritons
The surface plasmon resonance (SPR) phenomenon has been known for nearly five decades now; since then this method has made great advances in terms of instrumentation development and applications, and it still attracts researchers because of certain subtle issues that could benefit from it mainly detection and analysis of chemical and biochemical substances in different areas including medicine, environmental monitoring, biotechnology and drug and food monitoring. Our interest is focused on the use of this technique for studying thin coating and some application in nanophotonics. In this paper, we discuss the configuration of surface plasmons at air/metal interface by Atenuated total reflection (ATR) technique in the Kretchman configuration, and we present preliminary experimental results on surface plasmons at a Ag/air interface that we obtained in our laboratory.The surface plasmon resonance (SPR) phenomenon has been known for nearly five decades now; since then this method has made great advances in terms of instrumentation development and applications, and it still attracts researchers because of certain subtle issues that could benefit from it mainly detection and analysis of chemical and biochemical substances in different areas including medicine, environmental monitoring, biotechnology and drug and food monitoring. Our interest is focused on the use of this technique for studying thin coating and some application in nanophotonics. In this paper, we discuss the configuration of surface plasmons at air/metal interface by Atenuated total reflection (ATR) technique in the Kretchman configuration, and we present preliminary experimental results on surface plasmons at a Ag/air interface that we obtained in our laboratory
Dissipative dynamics of circuit-QED in the mesoscopic regime
We investigate the behavior of a circuit QED device when the resonator is
initially populated with a mesoscopic coherent field. The strong coupling
between the cavity and the qubit produces an entangled state involving
mesoscopic quasi-pointer states with respect to cavity dissipation. The overlap
of the associated field components results in collapse and revivals for the
Rabi oscillation. Although qubit relaxation and dephasing do not preserve these
states, a simple analytical description of the dissipative dynamics of the
circuit QED device including cavity relaxation as well as qubit dissipation is
obtained from the Monte-Carlo approach. Explicit predictions for the
spontaneous and induced Rabi oscillation signals are derived and sucessfully
compared with exact calculations. We show that these interesting effects could
be observed with a 10 photon field in forthcoming circuit QED experiments.Comment: 10 figures, 1 tabl
Strabisme aigu révélant une hypertension intracrânienne idiopathique associée à l’hormone de croissance Acute Strabismus Revealing Idiopathic Intracranial Hypertension Associated with Growth Hormone
Introduction : l’hypertension intracrânienne idiopathique associée l’hormone de croissance recombinant (rhGH)  est rare. Son diagnostic nécessite l’élimination de  toutes les étiologies d’hypertension intracrânienne. But : attirer l’attention des neuro-ophtalmologistes pédiatres sur les différentes présentations cliniques et les complications ophtalmologiques possible de cette pathologie.Observation : fille âgé de 11 ans suivie pour syndrome polyuropolydipsique et un retard staturopondéral secondaire à un déficit en hormone de croissance. L’exploration neuroradiologique a montré une interruption de la tige pituitaire. Elle a été mise sous desmopressine depuis 5 ans remplacée par   somatropine durant les   6 derniers  mois.La patiente a présenté de façon aigue un tableau d’hypertension intracrânienne idiopathique. L’évolution a été favorable dès le quinzième jour après arrêt initial de rhGH associé à l’acétazolamide.  A partir du troisième mois une  réintroduction  de l’hormone a été effectuée à des doses plus faibles sans récidive après un an de reculConclusion : l’hormone de croissance expose au risque d’HICI qui peut mettre en jeu  la fonction visuelle, s’elle n’est pas  traitée précocement. D’ou l’intérêt d’un suivi ophtalmologique chez les patients recevant ce traitemen
Case Report Bilateral Ewing Sarcoma/Primitive Neuroectodermal Tumor of the Breast: A Very Rare Entity and Review of the Literature
Peripheral primitive neuroectodermal tumors (PNET) are rare malignant tumors, affecting mostly children and adolescents and have been described in breast in eight case reports only. In this paper, we present a case of bilateral mammary ES/PNET where distinction between primary and metastatic diseases was discussed through a literature review. The aim of this work is to demonstrate that although rare, the possibility of PNET should be kept in mind while evaluating a palpable breast abnormality in a young female
Bilateral Ewing Sarcoma/Primitive Neuroectodermal Tumor of the Breast: A Very Rare Entity and Review of the Literature
Peripheral primitive neuroectodermal tumors (PNET) are rare malignant tumors, affecting mostly children and adolescents and have been described in breast in eight case reports only. In this paper, we present a case of bilateral mammary ES/PNET where distinction between primary and metastatic diseases was discussed through a literature review. The aim of this work is to demonstrate that although rare, the possibility of PNET should be kept in mind while evaluating a palpable breast abnormality in a young female
Shedding Light on the Chemical Diversity of Ectopic Calcifications in Kidney Tissues: Diagnostic and Research Aspects
In most industrialized countries, different epidemiologic studies show that chronic renal failure is dramatically increasing. Such major public health problem is a consequence of acquired systemic diseases such as type II diabetes, which is now the first cause for end stage renal failure. Furthermore, lithogenic diseases may also induce intratubular crystallization, which may finally result in end-stage renal failure (ESRF). Up to now, such rare diseases are often misdiagnosed. In this study, based on twenty four biopsies, we show that SR µFTIR (Synchrotron Radiation-µFourier transform infrared) spectroscopy constitutes a significant opportunity to characterize such pathological µcalcifications giving not only their chemical composition but also their spatial distribution in the tissues. This experimental approach offers new opportunities to the clinicians to describe at the cell level the physico-chemical processes leading to the formation of the pathological calcifications which lead to ESRF
- …