170,205 research outputs found
Binding to DPF-motif by the POB1 EH domain is responsible for POB1-Eps15 interaction
No full textBackground. Eps15 homology (EH) domains are protein interaction modules binding to peptides containing Asn-Pro-Phe (NPF) motifs and mediating critical events during endocytosis and signal transduction. The EH domain of POB1 associates with Eps15, a protein characterized by a striking string of DPF triplets, 15 in human and 13 in mouse Eps15, at the C-terminus and lacking the typical EH-binding NPF motif. Results. By screening a multivalent nonapeptide phage display library we have demonstrated that the EH domain of POB1 has a different recognition specificity since it binds to both NPF and DPF motifs. The region of mouse Eps15 responsible for the interaction with the EH domain of POB1 maps within a 18 amino acid peptide (residues 623-640) that includes three DPF repeats. Finally, mutational analysis in the EH domain of POB1, revealed that several solvent exposed residues, while distal to the binding pocket, mediate specific recognition of binding partners through both hydrophobic and electrostatic contacts. Conclusion. In the present study we have analysed the binding specificity of the POB1 EH domain. We show that it differs from other EH domains since it interacts with both NPF- and DPF-containing sequences. These unusual binding properties could be attributed to a different conformation of the binding pocket that allows to accommodate negative charges; moreover, we identified a cluster of solvent exposed Lys residues, which are only found in the EH domain of POB1, and influence binding to both NPF and DPF motifs. The characterization of structures of the DPF ligands described in this study and the POB1 EH domain will clearly determine the involvement of the positive patch and the rationalization of our findings. © 2007 Santonico et al; licensee BioMed Central Ltd
How and when auditory action effects impair motor performance
No full textMusic performance is characterized by complex cross-modal interactions, offering a remarkable window into training-induced long-term plasticity and multimodal integration processes. Previous research with pianists has shown that playing a musical score is affected by the concurrent presentation of musical tones. We investigated the nature of this audio-motor coupling by evaluating how congruent and incongruent cross-modal auditory cues affect motor performance at different time intervals. We found facilitation if a congruent sound preceded motor planning with a large Stimulus Onset Asynchrony (SOA −300 and −200 ms), whereas we observed interference when an incongruent sound was presented with shorter SOAs (−200, −100 and 0 ms). Interference and facilitation, instead of developing through time as opposite effects of the same mechanism, showed dissociable time-courses suggesting their derivation from distinct processes. It seems that the motor preparation induced by the auditory cue has different consequences on motor performance according to the congruency with the future motor state the system is planning and the degree of asynchrony between the motor act and the sound presentation. The temporal dissociation we found contributes to the understanding of how perception meets action in the context of audio-motor integration
L'integrazione audiomotoria nei musicisti: quando il suono disturba l'esecuzione
No full textAudiomotor integration constitutes an important field of research for psychology and cognitive neuroscience. Musical execution is a particular case of cross-modal integration that requires a complex interaction between output processes of motor production and planning, and the processing of input sensory information. In this context has been recently demonstrates that the process of motor planning in musical execution can be facilitated or inhibited in case of the contemporary presentation of a sound, respectively congruent or incongruent with the note to be played. This work contributes to define this effect: in particular we tried to verify, with the introduction of a baseline, if facilitation and inhibition processes can be defined in absolute terms, rather than relative.
Results have been interpreted as an evidence of inhibition of the motor plan caused by incongruent sounds, and absence of inhibition in the case of congruent sounds
Equivalent electric circuits for chemical sensors in the Langmuir regime
No full texttThis paper presents an equivalent electric circuit model that describes adsorption-desorption processesoccurring on bio and chemical sensor surfaces under the Langmuir hypothesis and considers the followingpractical case: the pressure or concentration of the particles in the test chamber is not perturbed bythese processes and keeps its initial value, as in the cases of relatively high pressure or concentrationvalues with zero molecular flow, or in the presence of a molecular flow at any pressure or concentrationvalue. It is also pointed out that the equivalent circuit for Langmuir adsorption is similar to the circuitproposed for enzymatic reactions. Even if this work essentially covers theoretic aspects, a way is suggestedfor the possible experimental determination of both adsorption-desorption parameters and adsorption-desorption site density
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Streamer suppression with SF6 in RPCs operated in avalanche mode
No full textWe show that the addition of small amounts of sulphur hexafluoride, SF6, to the present ATLAS baseline gas mixture C2H2F4/C4H10 has a very strong effect in suppressing the avalanche-to-streamer transition. An RPC of 50 x 50 cm(2) area, 2 mm gas gap was operated in pure avalanche, streamer-free mode in a voltage range of about 1 kV. The results of the test suggest that the observed fast signal could be interpreted as the sum of contributions of a number of primary saturated avalanches. (C) 1998 Elsevier Science B.V. All rights reserved
Trifolio arvense, Absintio santonico, Digitalis alba
No full text1. Nome scientifico: Trifolium arvense L.
(Fabaceae, Leguminosae)
Nome attuale: Trifoglio arvense
2. Nome scientifico: Tanacetum vulgare L.
(Asteraceae, Compositae)
Nome attuale: Tanaceto
3. Nome scientifico: Digitalis lutea L.
(Scrophulariaceae)
Nome attuale: Erba aralda, Digitale giall
Mitomycin C in highly myopic eyes - Author reply
No full textOphthalmology. 2005 Feb;112(2):208-18; discussion 219.
Mitomycin C modulation of corneal wound healing after photorefractive keratectomy in highly myopic eyes.
Gambato C, Ghirlando A, Moretto E, Busato F, Midena E.
SourceRefractive Surgery Service and Antimetabolite Therapy Research Unit, Department of Ophthalmology, University of Padova, Padova, Italy.
Abstract
PURPOSE: To evaluate the role of topical mitomycin C in corneal wound healing (CWH) after photorefractive keratectomy (PRK) in highly myopic eyes.
DESIGN: Prospective, double-masked, randomized clinical trial.
PARTICIPANTS: Seventy-two eyes of 36 patients affected by high (>7 diopters) myopia.
METHODS: In each patient, one eye was randomly assigned to PRK with intraoperative topical 0.02% mitomycin C application, and the fellow eye was treated with a placebo. Postoperatively, mitomycin C-treated eyes received artificial tears (3 times daily, tapered in 3 months), whereas the fellow eye was treated with fluorometholone sodium 2% and artificial tears (3 times daily, tapered in 3 months).
MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), contrast sensitivity, manifest refraction, and biomicroscopy. Contrast sensitivity was determined using the Pelli-Robson chart. Corneal confocal microscopy documented CWH.
RESULTS: Mean follow-up was 18 months (range, 12-36). No side effects or toxic effects were documented. At 12-month follow-up examination, UCVAs (logarithm of the minimum angle of resolution) were 0.4+/-0.48 and 0.5+/-0.53 (P = .03) in mitomycin C-treated eyes and corticosteroid-treated eyes, respectively. At 1 year, corneal haze developed in 20% of corticosteroid-treated eyes, versus 0% of mitomycin C-treated eyes. At 12, 24, and 36 months, corneal confocal microscopy showed activated keratocytes and extracellular matrix significantly more evident in untreated eyes (Ps = 0.004, 0.024, and 0.046, respectively).
CONCLUSION: Topical intraoperative application of 0.02% mitomycin C can reduce haze formation in highly myopic eyes undergoing PRK.
Comment in
Ophthalmology. 2006 Feb;113(2):357; author reply 357-8
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
