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Conductive Component (conductive + component)
Selected AbstractsHearing loss in Fabry disease: data from the Fabry Outcome SurveyEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 9 2006S. Hegemann Abstract Background, Hearing loss is a common symptom in Fabry disease, but neither its natural course nor its aetiology has been defined precisely. The aim of this study was to provide a detailed epidemiological description of hearing impairment in patients in the Fabry Outcome Survey (FOS), which is the largest available database of Fabry patients. Materials and methods, Questionnaires were completed by 566 Fabry patients, of whom 316 reported ear-related symptoms. Pure-tone audiograms from 86 patients, performed before starting enzyme replacement therapy, were analysed and compared with age- and sex-specific normal values (International Organization for Standardization, ISO 7029). Results, When compared to an age-matched population (ISO 7029), 74% of patients had a threshold elevated above the 95th centile in at least one tested frequency. All frequencies were affected to a similar degree. However, only 14 patients (16%) were clinically affected by hearing impairment according to the age-independent World Health Organization (WHO) classification (mean threshold at 0·5, 1 and 2 kHz worse than 25 dB). Hearing loss was sensorineural in 63 patients (73%) of whom 7 patients (8%) had also a conductive component. One patient had a purely conductive hearing loss. Episodes of sudden hearing loss seemed to occur more frequently than in the general population. Men were affected earlier and more severely than women. Conclusions, Hearing in Fabry disease is significantly worse than in an age-matched general population but leads to clinically relevant hearing impairment in only 16% of cases. It resembles accelerated presbycusis with an additional Fabry-specific strial-type hearing loss. [source] Enhanced Charge Transportation in Semiconducting Polymer/Insulating Polymer Composites: The Role of an Interpenetrating Bulk InterfaceADVANCED FUNCTIONAL MATERIALS, Issue 11 2010Guanghao Lu Abstract The charge transportation in poly(3-butylthiophene) (P3BT)/insulating polymer composites is studied both microscopically and macroscopically. The increased mobility of free charge carriers, in particular hole mobility, contributes to the enhanced electrical conductivity of this semiconductor/insulator composite. The conductivity origin of the composite, as revealed by conductive-atomic force microscopy (C-AFM), comes mainly from the P3BT network, whose carrier mobility has been improved as a result of reduced activation energy for charge transportation upon forming an interface with the insulating matrix. Both the huge interfacial area and interconnected conductive component are morphologically required for the enhanced electrical property of the composite. An increased size of the P3BT domains, which correspondingly reduces the interfacial area between the two components, ruins the enhancement. This study clarifies the mechanism of the higher electrical properties achieved in a semiconducting polymer upon blending with an insulating polymer, which will further promote the development of these low-cost, easily processable, and environmentally stable composites. [source] Electrically Conductive Poly(DL -lactide)/Chitosan/Polypyrrole ComplexesMACROMOLECULAR RAPID COMMUNICATIONS, Issue 12 2006Ying Wan Abstract Summary: The fabrication of novel conductive poly(DL -lactide)/chitosan/polypyrrole complex membranes is reported. Using poly(DL -lactide)/chitosan blends as matrices and polypyrrole as a conductive component, several kinds of membranes with various compositions are prepared. A percolation threshold of polypyrrole as low as 1.8 wt.-% is achieved for some membranes by controlling the chitosan proportion between 40 and 50 wt.-%. SEM images exhibit that the membranes with a low percolation threshold show a two-phase structure which consists of poly(DL -lactide) and chitosan phases. Dielectric measurements indicate that there is limited miscibility between the poly(DL -lactide) and chitosan but polypyrrole is nearly immiscible with the other two components. Based on the structural characteristics of the membranes, the polypyrrole particles are suggested to be localized at the interface between two phases. Dependence of conductivity of complex membranes on the PPy content. (,) PDLLA/PPy, (,) PDLLA/ch(10)/PPy, (,) PDLLA/ch(20)/PPy, (,) PDLLA/ch(30)/PPy, (,) PDLLA/ch(40)/PPy, and (,) PDLLA/ch(50)-PPy. [source] Design and development of a prototype endocavitary probe for high-intensity focused ultrasound delivery with integrated magnetic resonance imagingJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 3 2007Iain P. Wharton MRCS Abstract Purpose To integrate a high intensity focused ultrasound (HIFU) transducer with an MR receiver coil for endocavitary MR-guided thermal ablation of localized pelvic lesions. Materials and Methods A hollow semicylindrical probe (diameter 3.2 cm) with a rectangular upper surface (7.2 cm × 3.2 cm) was designed to house a HIFU transducer and enable acoustic contact with an intraluminal wall. The probe was distally rounded to ease endocavitary insertion and was proximally tapered to a 1.5-cm diameter cylindrical handle through which the irrigation tubes (for transducer cooling) and electrical connections were passed. MR compatibility of piezoceramic and piezocomposite transducers was assessed using gradient-echo (GRE) sequences. The radiofrequency (RF) tuning of identical 6.5 cm × 2.5 cm rectangular receiver coils on the upper surface of the probe was adjusted to compensate for the presence of the conductive components of the HIFU transducers. A T1-weighted (T1-W) sliding window dual-echo GRE sequence monitored phase changes in the focal zone of each transducer. High-intensity (2400 W/cm,2), short duration (<1.5 seconds) exposures produced subtherapeutic temperature rises. Results For T1-W images, signal-to-noise ratio (SNR) improved by 40% as a result of quartering the conductive surface of the piezoceramic transducer. A piezocomposite transducer showed a further 28% improvement. SNRs for an endocavitary coil in the focal plane of the HIFU trans-ducer (4 cm from its face) were three times greater than from a phased body array coil. Local shimming improved uniformity of phase images. Phase changes were detected at subtherapeutic exposures. Conclusion We combined a HIFU transducer with an MR receiver coil in an endocavitary probe. SNRs were improved by quartering the conductive surface of the piezoceramic. Further improvement was achieved with a piezocomposite transducer. A phase change was seen on MR images during both subtherapeutic and therapeutic HIFU exposures. J. Magn. Reson. Imaging 2007. © 2007 Wiley-Liss, Inc. [source] | |||||||||||||