Speech feature recognition by profoundly hearing impaired children using a multiple-channel electrotactile speech processor and aided residual hearing

A group of prelinguistically hearing impaired children, between 7 and 11 years of age, were trained in the perception of vowel duration and place, the fricative /s/, and manner of articulation (/m/ vs /b/ and /s/ vs /t/) distinctions, using information provided by a multiple-channel electrotactile aid (Tickle Talker), and through aided hearing. Training was provided in the tactile-plus-aided hearing (TA) and tactile (T) conditions. Speech feature recognition tests were conducted in the TA, T, and aided hearing (A) conditions, during pretraining, training, and post-training phases. Test scores in the TA and T conditions were significantly greater than scores in the A condition for all tests, suggesting that perception of these features was improved when the tactile aid was worn. Test scores in the training and post-training phases were significantly greater than in the pretraining phase, suggesting that the training provided was responsible for the improvement in feature perception. Statistical analyses demonstrated a significant interaction between the main effects of condition and phase, suggesting that training improved perception in the TA and T conditions, but not in the A condition. Post-training and training test scores were similar suggesting that the perceptual skills acquired during training were retained after the removal of training. Recognition of trained features improved for trained, as well as for untrained words.     

Opportunities for measurements of astrophysical-relevant alpha-capture reaction rates at CRYRING@ESR

The heavy-ion storage ring CRYRING@ESR has recently been installed and commissioned at GSI as one of the first installations of the upcoming Facility for Antiproton and Ion Research (FAIR). It is designed to store highly charged ions in the energy range between 300 keV/u and about 10 MeV/u. It will incorporate a gas-jet target providing high-density jets of, among other gases, hydrogen and helium. This will allow to study alpha-capture reaction rates of astrophysical interest in the energy range of the Gamow window for core-collapse supernovae. Special interest comes from the long-lived radio-isotope ⁴⁴Ti (t_1/2 = 58.9 years), which is supposed to be produced in the alpha-rich freeze-out during such an event. The nucleosynthesis of this isotope is of great interest, as the amount of material produced can be estimated by direct observation in remnants of recent supernovae. The disagreements between the observations and the estimations from astrophysical models show the need of more experimental data for the production and consumption reactions in the energy range of a core-collapse supernova. In this article, we will describe the proposed method of injecting beams of ⁴⁴Ti into CRYRING@ESR and performing the actual reaction rate measurements.     

Resistive and Magnetic Susceptibility Transitions in Superconducting (TMTSF)2C104

We report measurements of the ac magnetic susceptibility and dc resistive superconducting transitions in the organic superconductor (TMTSF)₂C10₄. Inductive measurements show complete diamagnetic shielding below a broad transition and initial flux penetration at very low fields [H_c1(0) < 1 Oe]. The resistive transition is also broad, but occurs at a significantly higher temperature than the inductive transition, T_c = 1.0 K and 0.65 K respectively. Resistance measurements also show evidence of a phase transition in the vicinity of 24 K. Magnetic field induced transitions, measured both inductively and resistively, show marked anistropy both in magnitude and in breadth of the transition. Results suggest that (TMTSF)₂C10₄ is a quasi ID or 2D superconductor at high temperatures and high magnetic fields and an anisotropic bulk superconductor at low temperatures and fields. Associated thermoelectric power measurements suggest that spin density waves coexist with the superconducting state.     

Dose-controlled irradiation of cancer cells with laser-accelerated proton pulses

Proton beams are a promising tool for the improvement of radiotherapy of cancer, and compact laser-driven proton radiation (LDPR) is discussed as an alternative to established large-scale technology facilitating wider clinical use. Yet, clinical use of LDPR requires substantial development in reliable beam generation and transport, but also in dosimetric protocols as well as validation in radiobiological studies. Here, we present the first dose-controlled direct comparison of the radiobiological effectiveness of intense proton pulses from a laser-driven accelerator with conventionally generated continuous proton beams, demonstrating a first milestone in translational research. Controlled dose delivery, precisely online and offline monitored for each out of ～4,000 pulses, resulted in an unprecedented relative dose uncertainty of below 10 %, using approaches scalable to the next translational step toward radiotherapy application.     

DNA nuclease activity of Rev-coupled transition metal chelates

Artificial nucleases containing Rev-coupled metal chelates based on combinations of the transition metals Fe(2+), Co(2+), Ni(2+), and Cu(2+) and the chelators DOTA, DTPA, EDTA, NTA, tripeptide GGH, and tetrapeptide KGHK have been tested for DNA nuclease activity. Originally designed to target reactive transition metal chelates (M-chelates) to the HIV-1 Rev response element mRNA, attachment to the arginine-rich Rev peptide also increases DNA-binding affinity for the attached M-chelates. Apparent K(D) values ranging from 1.7 to 3.6 μM base pairs for binding of supercoiled pUC19 plasmid DNA by Ni-chelate-Rev complexes were observed, as a result of electrostatic attraction between the positively-charged Rev peptide and negatively-charged DNA. Attachment of M-chelates to the Rev peptide resulted in enhancements of DNA nuclease activity ranging from 1-fold (no enhancement) to at least 13-fold (for Cu-DTPA-Rev), for the rate of DNA nicking, with second order rate constants for conversion of DNA(supercoiled) to DNA(nicked) up to 6 × 10(6) M(-1) min(-1), and for conversion of DNA(nicked) to DNA(linear) up to 1 × 10(5) M(-1) min(-1). Freifelder-Trumbo analysis and the ratios of linearization and nicking rate constants (k(lin)/k(nick)) revealed concerted mechanisms for nicking and subsequent linearization of plasmid DNA for all of the Rev-coupled M-chelates, consistent with higher DNA residency times for the Rev-coupled M-chelates. Observed rates for Rev-coupled M-chelates were less skewed by differing DNA-binding affinities than for M-chelates lacking Rev, as a result of the narrow range of DNA-binding affinities observed, and therefore relationships between DNA nuclease activity and other catalyst properties, such as coordination unsaturation, the ability to consume ascorbic acid and generate diffusible radicals, and the identity of the metal center, are now clearly illustrated in light of the similar DNA-binding affinities of all M-chelate-Rev complexes. This work paints a clearer picture of the factors governing DNA nuclease activity by redox active M-chelates than was previously possible. The results demonstrate enhancement of DNA cleavage by use of a targeting sequence, but also clearly underscore that significant orientational factors are required for optimal reactivity at the metal center. Moreover, the studies confirm high selectivity for the target HIV RRE RNA at the most likely dosage concentrations, lending further support to the feasibility of designing and applying targeted catalytic metallodrugs.     

Heteroleptic N6 coordinated ruthenium(II) complexes as building blocks for the formation of discrete Ru2Ag2 complexes

A heteroleptic N(6) coordinated Ru(II) complex acts as a building block for a discrete tetranuclear mixed metal Ru(II)(2)Ag(I)(2) coordination compound; both complexes have been structurally characterised by X-ray crystallography.     

The role of cobalt phosphate in enhancing the photocatalytic activity of α-Fe2O3 toward water oxidation

Transient absorption spectroscopy was used to probe the dynamics of photogenerated charge carriers in α-Fe(2)O(3)/CoO(x) nanocomposite photoelectrodes for water splitting. The addition of cobalt-based electrocatalysts was observed to increase the lifetime of photogenerated holes in the photoelectrode by more than 3 orders of magnitude without the application of electrical bias. We therefore propose that the enhanced photoelectrochemical activity of the composite electrode for water photooxidation results, at least in part, from reduced recombination losses because of the formation of a Schottky-type heterojunction.     

The surface ace plasmon resonance effect in holography

A hologram has been made using a surface plasmon resonance wave as the reference beam. The surface wave was stimulated on a 1200-line/mm aluminum reflection grating that was coated with a thin layer of high resolution photographic emulsion. Experimental results are presented.