862 research outputs found
Synthesis and electrochemical behavior of a model redox-active thiacalix[4]arene-tetrathiafulvalene assembly
Syntheses of the first bisthiacalix[4]arenes systems bridged by a tetrathiafulvalene (TTF) framework have been carried out through triethyl phosphite-mediated dechalcogenation dimerization of the corresponding 1,3-dithiole-2-ones. The cyclic voltammograms of the resulting bisthiacalix[4]arenes tethered by an electroactive TTF unit are provided, and exhibit an electrochemical response in the case of introduction of Ag+
Carboxylic acid derivatives of tetrathiafulvalene: key intermediates for the synthesis of redox-active calixarene-based anion receptors
A series of calixareneâTTF (TTF=tetrathiafulvalene) receptors incorporating amide binding units for anion recognition have been synthesized and characterized. For this purpose, two synthetically versatile new TTF carboxylic acid derivatives were prepared and characterized by X-ray diffraction, these structures demonstrating the critical role of the carboxylic function in the solid-state organization. Some of the calixareneâamideâTTF assemblies exhibit strong binding of various anions, as shown by 1H NMR titration studies, and one receptor is able to electrochemically respond in the presence of H2PO4â, C6H5CO2â or CH3CO2â anion
TTF-Podants and TTF-Calixarene assemblies : original striuctural solutions towards redoxresponsive ligands
Understanding the effect of saturated gases on catalytic performance of graphiticâcarbon nitride (gâC<sub>3</sub>N<sub>4</sub>) for H<sub>2</sub>O<sub>2</sub> generation and dye degradation in the presence of ultrasound
This paper examines the effect of saturated gases on H2O2 generation and dye degradation using graphiticâcarbon nitride (gâC3N4) as a piezoelectric catalyst. A detailed catalytic evaluation was carried out using a doubleâbath sonoâreactor, where the performance of gâC3N4 for H2O2 production and degradation of rhodamine B and indigo carmine dyes was evaluated for a range of catalyst dosage levels and saturated gases. Specific gases were selected to understand their role in the sonochemical production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) and to elucidate the potential catalytic mechanism. The use of an ArâO2 gas mixture led to the highest yield for H2O2 production and dye degradation due to the positive effect of argon and oxygen in the generation of H2O2 and reactive oxygen species, respectively. The presence of nitrogen in both air and in an Arâair mixture increased H2O2 generation since reactive nitrogen species improved the conversion of âąOH into H2O2. In contrast, air and Arâair negatively influenced the generation of ROS, which resulted in a low rate of dye degradation. This work provides new insights of the mechanisms of sonochemical and piezocatalytic processes in the use of graphiticâcarbon nitride in catalytic applications.This article is protected by copyright. All rights reserved
Pilot Testing of Assessment of Capacity for Myoelectric Control (ACMC) in Evaluating Myoelectric Hand Function in Chinese Population
Upper limb amputations cause marked functional disability and lower the individualâs self-body image, with severepsychological implications. Many rehabilitation parameters are involved in the successful rehabilitation of upper limbamputations. The aim of this study was to examine the validity and reliability of the Chinese version of Assessment ofCapacity for Myoelectric Control (Chinese-ACMC) in upper limb amputated subjects and with a myo-electric-poweredprosthetic hand.To validate the Chinese version of Assessment of Capacity for Myoelectric Control (Chinese-ACMC) in upper limbamputee subjects (children and adults) with a myo-electric-powered prosthetic hand. A sample of convenience samplingof 22 subjects (11 males, 11 females) with upper limb amputation and myoelectric prosthetic hands were recordedduring a regular clinical visit for ACMC. Each subject was evaluated according to four criteria: (a) Upper Limb Amputationincluding all levels of amputation; (b) No specific pain type â no matter phantom or pain in the stump; (c) With intactcognitive function; (d) Age ranged from 12 to 40 years. With instruction, occupational therapists and prosthetic-orthoticswith at least twenty yearsâ clinical experience of myoelectric prosthesis training would conduct the 30-items ChineseACMC for each subject. A serial of errand tasks of activities of daily living were designed for evaluation. Individualsâratings were repeated after 4 weeks. Through test-retest reliability, internal consistency testing, factor analysis, intra andinter factor correlation analysis. A four-factor structure, namely, âGrippingâ, âHoldingâ, âReleasingâ and âCoordinatingâare identified
Space Weather Application Using Projected Velocity Asymmetry of Halo CMEs
Halo coronal mass ejections (HCMEs) originating from regions close to the
center of the Sun are likely to be responsible for severe geomagnetic storms.
It is important to predict geo-effectiveness of HCMEs using observations when
they are still near the Sun. Unfortunately, coronagraphic observations do not
provide true speeds of CMEs due to the projection effects. In the present
paper, we present a new technique allowing estimate the space speed and
approximate source location using projected speeds measured at different
position angles for a given HCME (velocity asymmetry). We apply this technique
to HCMEs observed during 2001-2002 and find that the improved speeds are better
correlated with the travel times of HCMEs to Earth and with the magnitudes
ensuing geomagnetic storms.Comment: accepted for [publication in Solar Physic
Ferrocenyl-triazolyl-tetrathiafulvalene assemblies: synthesis and electrochemical recognition properties
Cu(I)-catalyzed HuisgenâMeldalâSharpless type dipolar âclickâ reactions between azido-tetrathiafulvalene derivatives and ethynylferrocene yield the first examples of ferrocenyl-1,2,3-triazolyl-tetrathiafulvalene assemblies (4a, 4b). The electrochemical behavior of 4a and 4b, which integrate two distinctive redox probes, has been investigated, and their binding ability for various transition-metal cations has been studied by cyclic voltammetry. The contribution of the triazolyl ring in the guest binding process is illustrated by the specific electrochemical recognition of Zn2+ by receptor 4b
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