Discrimination of temporal asymmetry in cochlear implantees

Several studies have recently demonstrated that normal-hearing listeners are sensitive to short-term temporal asymmetry in the envelopes of sinusoidal or noise carriers. This paper presents a study in which cochlear implantees were presented trains of current pulses with temporally asymmetric envelopes through one channel of an implant that stimulates the auditory nerve directly, thereby bypassing cochlear processes. When the level of the stimuli was adjusted to fit their audibility range, the implantees were able to discriminate temporal asymmetry over a much wider range than normal-hearing listeners. The results suggest that the perception of temporal asymmetry is limited by compression in the normal cochlea.     

High-Resolution Infrared Spectrum of Vinyl Fluoride at 500 cm-1

The infrared spectrum of vinyl fluoride (CH2=CHF) has been investigated in the region 390-590 cm-1 at room temperature and at a resolution of 0.0016 cm-1 using a Fourier transform spectrometer. The rovibrational analysis of the spectral features allowed us to assign about 11 000 lines (J 相似文献   

Visual and verbal short-term memory deficits in childhood leukemia survivors after intrathecal chemotherapy

Assessed survivors of childhood lymphoblastic leukemia (ALL) treated with intrathecal chemotherapy, using the Wide Range Assessment of Memory and Learning (WRAML), compared to controls without cancer, matched as closely as possible in age, SES, and gender. Mild, but consistent, deficits were found in both visual-spatial and verbal single-trial memory tasks. In multitrial learning, only visual-spatial tasks resulted in deficient scores, while verbal learning was within the normal range. IQ results indicated scores 10-20 points lower in the ALL group. Memory results are related to deficits in strategic planning and attentional distractiveness. The WRAML may be a useful clinical tool to evaluate differential memory deficits in children with ALL.     

A brief history of twin study methods

In order to clarify the role of phosphatidylcholine-specific phospholipase C (PC-PLC) in the regulation of apoptosis in vascular endothelial cells (VEC), we investigated the effects of D609, a specific inhibitor of PC-PLC, on apoptosis that was induced by deprivation of fibroblast growth factor (FGF) and serum and also by rattlesnake venom. The early morphological changes (detachment of cells from dishes) and the fragmentation of DNA, which is a specific feature of apoptotic cell death, were clearly inhibited by D609 in these two apoptosis-inducing systems. Moreover, the production of diacylglycerol (DAG), which was stimulated in apoptotic VEC, was suppressed by D609. The effects of D609 on the activity of PC-PLC and on apoptosis of VEC were dose-dependent. Our results indicate that PC-PLC is involved in the apoptosis-inducing signal pathway in VEC and, that DAG, produced from phosphatidylcholine (PC), might be an important mediator in this signal-transduction pathway. Our results also suggest that rattlesnake venom, a strong promoter of apoptosis in VEC, might induce apoptosis by stimulating PC-PLC and, furthermore, that PC-PLC might play a significant role in anchorage-dependent signal transduction in VEC.     

Evaluation of commercially available materials to mitigate insect residue adhesion on wing leading edge surfaces

Surface contamination from insect strikes on aircraft wing leading edges can induce localized boundary layer transition from laminar to turbulent flow, resulting in increased aerodynamic drag and reduced fuel efficiency. As aviation fuel costs continue to climb, strategies to reduce fuel burn using laminar flow have led to renewed interest in surface modifications to minimize the effects of insect residue adhesion on aircraft wings. Under NASA's Environmentally Responsible Aviation Program, insect residue adhesion-resistant coatings are being studied as an approach for drag reduction. A series of aluminum alloy test surfaces were coated with commercially available materials and characterized using contact angle goniometry. The surfaces were subsequently subjected to controlled impact of crickets using a custom-built pneumatic insect delivery device. Impact events were recorded and analyzed using high-speed digital photography and characterized using optical surface profilometry. Residue adhesion was observed on all of the coatings investigated. The cricket impact event was related to liquid droplets impacting surfaces at high velocities and was analyzed as such. Coating surface energy was determined to influence residue adhesion.     

Polymeric receptors for the recognition of folic acid and related compounds via substructure imprinting

A range of 2-acrylamidopyridines, showing subtle differences in solution binding toward carboxylic acids, has been investigated as functional monomers in molecular imprinting. Imprinting of N-Z-L-glutamic acid with one such monomer is shown to be effective in the creation of a molecularly imprinted polymer (MIP) with recognition properties for its template and also for larger molecules containing glutamic acid residues. In comparison to a MIP prepared via a more "traditional" approach, the new polymeric receptors exhibit reduced nonspecific binding. The new receptors are compared with previously reported urea-based receptors targeting the glutamic acid residue and receptors targeting the pteridine substructure of folic acid.     

Modeling of epoxy resin spacers for the 1 MV DC gas insulated line of ITER neutral beam injector system

The spacers for the Gas Insulated Transmission Line for the ITER neutral beam injector will be designed to withstand the operating voltage of 1 MV dc. Electric charging processes of the spacer surface are then expected to play an important role in the final electric field distribution. Aim of the paper is to investigate the effects of the different conductivity properties of the SF6-Spacer insulating structures on the surface charge set-up, and to identify a procedure to minimize this charge. Based on the most updated literature, the paper presents and discusses the results of two newly developed simulation tools: the first consisting of a quasi-static non linear model for epoxy spacer based on finite element method code ANSYS?, the other consisting of a spacer profile optimization package, whose kernel is based on a genetic algorithm. The numerical tools have been applied to post and disk spacer models of the gas insulated line; in particular, the optimization package has been used on the disk spacer, and the comparison between un-optimized and optimized spacer in terms of electric charge accumulated are presented and discussed.