High-resolution and functional magnetic resonance imaging of the brachial plexus using an isotropic 3D T2 STIR (Short Term Inversion Recovery) SPACE sequence and diffusion tensor imaging

This technical note demonstrates the relevance of the isotropic 3D T2 turbo-spin-echo (TSE) sequence with short-term inversion recovery (STIR) and variable flip angle RF excitations (SPACE: Sampling Perfection with Application optimized Contrasts using different flip angle Evolutions) for high-resolution brachial plexus imaging. The sequence was used in 11 patients in the diagnosis of brachial plexus pathologies involving primary and secondary tumors, and in six volunteers. We show that 3D STIR imaging is not only a reliable alternative to 2D STIR imaging, but it also better evaluates the anatomy, nerve site compression and pathology of the plexus, especially to depict space-occupying tumors along its course. Finally, due to its appropriate contrast we describe how 3D-STIR can be used as a high-resolution mask to be fused with fraction of anisotropy (FA) maps calculated from diffusion tensor imaging (DTI) data of the plexu

Novel enzyme-free multifunctional bentonite/polypyrrole/silver nanocomposite sensor for hydrogen peroxide detection over a wide pH range

Precise designs of low-cost and efficient catalysts for the detection of hydrogen peroxide (H2O2) over wide ranges of pH are important in various environmental applications. Herein, a versatile and ecofriendly approach is presented for the rational design of ternary bentonite-silylpropyl-polypyrrole/silver nanoarchitectures (denoted as BP-PS-PPy/Ag) via the in-situ photo polymerization of pyrrole with salinized bentonite (BP-PS) in the presence of silver nitrate. The Pyrrolyl-functionalized silane (PS) is used as a coupling agent for tailoring the formation of highly exfoliated BP-PS-PPy sheet-like nanostructures ornamented with monodispersed Ag nanoparticles (NPs). Taking advantage of the combination between the unique physicochemical properties of BP-PS-PPy and the outstanding catalytic merits of Ag nanoparticles (NPs), the as-synthesized BP-PS-PPy/Ag shows a superior electrocatalytic reduction and high-detection activity towards H2O2 under different pH conditions (from 3 to 10). Intriguingly, the UV-light irradiation significantly enhances the electroreduction activity of H2O2 substantially, compared with the dark conditions, due to the high photoelectric response properties of Ag NPs. Moreover, BP-PS-PPy/Ag achived a quick current response with a detection limit at 1 μM within only 1 s. Our present approach is green, facile, scalable and renewabl

Fistules perilymphatiques post-traumatiques

Introduction : La fistule péri-lymphatique (FPL) post-traumatique réalise une communication anormale entre le compartiment liquidien périlymphatique et l’oreille moyenne. Son diagnostic est souvent difficile du fait du tableau clinique parfois incomplet. L’imagerie est indispensable afin d’étayer le diagnostic. Le traitement repose sur la chirurgie.Matériel et méthodes : Il s’agit d’une étude rétrospective à propos de 13 patients colligés sur une période de 13 ans (1996-2008). Un examen ORL complet, une audiométrie et une imagerie (tomodensitométrie des rochers) ont été réalisés dans tous les cas. Tous les patients ont bénéficié d’un traitement médical et ont été opérés sous anesthésie générale. Le contrôle ultérieur était clinique, audiométrique et radiologique avec un recul moyen de 22 mois.Résultats : L’âge moyen était de 29 ans (20-47 ans) et le sex-ratio 3,33. Les signes fonctionnels étaient essentiellement représentés par l’hypoacousie dans 12 cas (92,3%), les vertiges dans 11 cas (84,6%) et les acouphènes dans 4 cas (30,8%). L’écoulement d’un liquide eau de roche par l’oreille a été rapporté par 2 patients (15,4%). L’examen clinique trouvait un nystagmus spontané battant du côté controlatéral au traumatisme chez un seul patient, et un signe de la fistule positif chez 2 patients (15,4%). A l’audiométrie, 9 patients (69,3%) avaient une surdité de perception ou mixte dont 6 cas de cophose. Une surdité de transmission a été objectivée dans 3 cas. Un patient avait une audition subnormale. La TDM des rochers a montré une fracture extra-labyrinthique dans 5 cas (38,5%) et une fracture trans-labyrinthique ou mixte dans 6 cas (46,2%). Un pneumolabyrinthe a été constaté chez 5 patients (38,5%). Une exploration chirurgicale a été indiquée chez tous les patients. En per-opératoire, une FPL a été mise en évidence dans tous les cas. Le siège de la fistule était au niveau du promontoire et/ou au niveau des fenêtres. Un colmatage de la fistule a été réalisé dans tous les cas. Les matériaux utilisés étaient essentiellement de l’aponévrose temporale superficielle, du périchondre tragal et de la graisse. En post-opératoire, les vertiges se sont améliorés chez 9 patients parmi les 11 vertigineux (81,8%). L’audition était améliorée chez 2 patients parmi les 9 ayant une surdité de perception ou mixte (18,2%).Conclusion : La fistule périlymphatique post-traumatique est de diagnostic difficile. Celui-ci est étayé par un faisceau d’arguments cliniques et paracliniques et n’est confirmé qu’en per-opératoire. L’indication d’une exploration chirurgicale et son délai dépendent essentiellement de la symptomatologie clinique et de son évolution dans le temps.Mots-clés : fistule périlymphatique, traumatisme, vertige, surdité, tomodensitométrie, chirurgieIntroduction: Post-traumatic perilymphatic fistula (PLF) realises an abnormal communication between the perilymphatic fluid compartment and the middle ear. Its diagnosis is often difficult because the clinical presentation is sometimes incomplete. Imaging is essential in order to support the diagnosis. Treatment is based on surgery.Materials and Methods: We carry a retrospective study about 13 patients collected over a period of 13 years (1996-2008). A complete ENT examination, audiometry and imaging (petrous CT scan) were performed in all cases. All patients received medical treatment and were operated under general anaesthesia. Subsequent control was clinical, radiological and audiometric with a mean period of 22 months.Results: Mean age was 29 years (20-47 years) and sex ratio 3.33. Symptoms were mainly hearing loss in 12 cases (92.3%), vertigo in 11 cases (84.6%) and tinnitus in 4 cases (30.8%). Flow of liquid from the ear was reported by 2 patients (15.4%). Clinical examination showed spontaneous nystagmus beating to the contralateral side of the trauma in one patient, and a positive sign of the fistula in 2 patients (15.4%). At audiometry, 9 patients (69.3%) had sensorineural or mixed deafness, of which 6 cases of cophosis. Transmission deafness was found in 3 cases. One patient had a subnormal hearing. Petrous CT scan showed extra-labyrinthic fracture in 5 cases (38.5%) and trans-labyrinthic or mixed fracture in 6 cases (46.2%). A pneumolabyrinth was found in 5 patients (38.5%). Surgical exploration was indicated in all patients. PLF was found in all cases. The localization of the fistula was at the promontory and / or at the windows. Blockage of the fistula was achieved in all cases. Materials used were essentially superficial temporal fascia, tragal perichondrium and fat. Postoperatively, vertigo improved in 9 patients among 11 (81.8%). Hearing was improved in 2 patients among the 9 having sensorineural or mixed deafness (18.2%).Conclusion: Post-traumatic perilymphatic fistula trauma is difficult to diagnose. This is supported by a beam of clinical and paraclinical arguments, and is confirmed intraoperatively. The indication for surgical exploration and its delay depend mainly on clinical symptomatology and its evolution over time.Keywords: perilymphatic fistula, trauma, vertigo, deafness, CT scan, surger

Facile preparation of N-S co-doped graphene quantum dots (GQDs) from graphite waste for efficient humidity sensing

In this work, graphene quantum dots (GQDs) were prepared from Graphitic waste. The resulting GQDs were evaluated for the potential application for resistive humidity sensors. The resistive humidity sensors were fabricated on the pre-patterned interdigital ITO electrodes using the three different concentrations (2.5, 5.0, and 10 mg) of GQDs in DMF. The GQDs films were deposited using the spin coating technique. The GQDs (10 mg/ml) based impedance sensors showed good sensitivity and lowered hysteresis as compared to the other ratios (2.5 and 5 mg) of the GQDs. The maximum calculated hysteresis of the GQDs (10 mg) based humidity sensor is around 2.2 % at 30%RH, and the minimum calculated hysteresis of the GQDs (10 mg/ml) based humidity sensor is approximately 0.79 % at 60 %RH. The response and recovery time found to be 15 s and 55 s, respectively. The interesting humidity-dependent resistive properties of these prepared GQDs make them promising for potential application in humidity sensing.Scopu

Synthesis of in situ photoinduced halloysite-polypyrrole@silver nanocomposite for the potential application in humidity sensors

Halloysite-polypyrrole-silver nanocomposite has been prepared via in situ photopolymerizations of pyrrole in the presence of silanized halloysite and silver nitrate as a photoinitiator. The halloysite nanoclay (HNT) was modified using the hydrogen donor silane coupling agent (DMA) in order to provide anchoring sites for the polypyrrole/silver composite (PPy@Ag). The mass loadings for both PPy and Ag have been estimated to be 21 and 26 wt%, respectively. The anchored Ag particles were found in the metallic state. The resulting PPy@Ag-modified silanized HNT has been evaluated for the potential application for impedance humidity sensors. HNT-DMA-PPy@Ag nanocomposite with different weight % of PPy@Ag (0.25 wt%, 0.5 wt%, and 1 wt%) was deposited on the pre-patterned interdigital Indium Tin Oxide (ITO) electrodes by spin coating technique. The addition of Ag nanoparticles within the nanocomposite enhances the hydrophilicity of the sensing film, which improves the sensitivity of the humidity sensors. The HNT-DMA-PPy@Ag (0.5 wt%) nanocomposite-based impedance sensors showed good sensitivity and lowered hysteresis as compared to the other ratios of the composite. The maximum calculated hysteresis loss of the HNT-DMA-PPy@Ag (0.5 wt%)-based humidity sensor is around 4.5% at 80% RH (relative humidity), and the minimum hysteresis loss estimated to be 0.05% at 20% RH levels. The response and recovery time of HNT-DMA-PPy@Ag (0.5 wt%) nanocomposite-based impedance sensors were found to be 30 and 35 s, respectively. The interesting humidity-dependent impedance properties of this novel composite make it promising in humidity sensing.Scopu

Bentonite-decorated calix [4] arene: A new, promising hybrid material for heavy-metal removal

There is global concern about the contamination of ground, river, and tap waters as well as soil contamination with heavy metal ions; these chemical species are known to not degrade and to cause severe health problems if ingested by humans and animals. Such environmental and health concerns necessitate the development of ultrasensitive sensors and high-capacity adsorbents. This study demonstrates for the first time the potential of organophilic bentonite combined with tetra(2-pyridylmethyl)amide calix [4] arene as a high-performance hybrid material for the removal of toxic heavy metals. After consecutive synthesis steps, the modified bentonites were thoroughly characterized by FT-IR, XRD, UV spectroscopy, and TEM. In particular, the XRD analysis showed strong supporting evidence for intercalation in the clay following each modification step. The salient feature of the newly prepared hybrid material is its high extraction capacity for Cd(II) and Zn(II) metals, as determined by atomic absorption spectrometry and UV spectrometry. Different preparation methods, with respect to the quantity of the added cationic surfactant, were investigated to determine the optimal conditions for synthesis. The extraction percentage for the as-prepared hybrid material was measured to be as high as 97.4% and 94.2% for Cd(II) and Zn(II), respectively.This paper was made possible by the NPRP award [ 8-878-1-172 ] from Qatar National Research Fund (a member of the Qatar foundation ). The statements made herein are solely the responsibility of the Authors

Anti-corrosive and oil sensitive coatings based on epoxy/polyaniline/magnetite-clay composites through diazonium interfacial chemistry

Epoxy polymer nanocomposites filled with magnetite (Fe3O4) clay (B), named (B-DPA-PANI@Fe3O4) have been prepared at different filler loading (0.1, 0.5, 1, 3, 5 wt. %). The surface modification of clay by polyaniline (PANI) is achieved in the presence of 4-diphenylamine diazonium salt (DPA). The effects of the nanofiller loading on Tensile, mechanical and dielectric properties were systematically studied. Improved properties was highlighted for all reinforced samples. The addition of only 3 wt. % of the filler enhanced the tensile strength of the composites by 256%, and the glass transition temperature Tg by 37%. The dielectric spectra over a broad frequency showed a robust interface between the hybrid (B-DPA-PANI@Fe3O4) fillers and epoxy matrix. The results showed most significant improvement in corrosion inhibition using electrochemical impedance spectroscopy (EIS) in 3.5 wt % NaCl, as well as a significant response in oil sensing test. High charge transfer resistance of 110 � 106 ?.cm2 using 3-wt % of filler was noted compared to 0.35 � 106 ?.cm2 for the pure epoxy. The results obtained herein will open new routes for the preparation of efficient anticorrosion sensor coatings. � 2018, The Author(s).The NPRP Award [8-878-1-172] from the Qatar National Research Fund (a member of Qatar Foundation) made this manuscript possible.Scopu

Carbon Dioxide Methanation Enabled by Biochar-Nanocatalyst Composite Materials: A Mini-Review

Due to ever-increasing global warming, the scientific community is concerned with finding immediate solutions to reduce or utilize carbon dioxide (CO2) and convert it in useful compounds. In this context, the reductive process of CO2 methanation has been well-investigated and found to be attractive due to its simplicity. However, it requires the development of highly active catalysts. In this mini-review, the focus is on biochar-immobilized nanocatalysts for CO2 methanation. We summarize the recent literature on the topic, reporting strategies for designing biochar with immobilized nanocatalysts and their performance in CO2 methanation. We review the thermochemical transformation of biomass into biochar and its decoration with CO2 methanation catalysts. We also tackle direct methods of obtaining biochar nanocatalysts, in one pot, from nanocatalyst precursor-impregnated biomass. We review the effect of the initial biomass nature, as well as the conditions that permit tuning the performances of the composite catalysts. Finally, we discuss the CO2 methanation performance and how it could be improved, keeping in mind low operation costs and sustainability