4,416 research outputs found
Velum movement detection based on surface electromyography for speech interface
Conventional speech communication systems do not perform well in the absence of an intelligible acoustic signal. Silent Speech Interfaces enable speech communication to take place with speech-handicapped users and in noisy environments. However, since no acoustic signal is available, information on nasality may be absent, which is an important and relevant characteristic of several languages, particularly European Portuguese. In this paper we propose a non-invasive method - surface Electromyography (EMG) electrodes - positioned in the face and neck regions to explore the existence of useful information about the velum movement. The applied procedure takes advantage of Real-Time Magnetic Resonance Imaging (RT-MRI) data, collected from the same speakers, to interpret and validate EMG data. By ensuring compatible scenario conditions and proper alignment between the EMG and RT-MRI data, we are able to estimate when the velum moves and the probable type of movement under a nasality occurrence. Overall results of this experiment revealed interesting and distinct characteristics in the EMG signal when a nasal vowel is uttered and that it is possible to detect velum movement, particularly by sensors positioned below the ear between the mastoid process and the mandible in the upper neck region.info:eu-repo/semantics/publishedVersio
Effect of Polymer Hydration on the Kinetic Release of Drugs: A Study of Ibuprofen and Ketoprofen in HPMC Matrices
Samples of drug/hydroxypropylmethylcellulose (HPMC) mixtures and matrices (drug/HPMC mixtures plus excipients) were allowed to equilibrate in closed chambers with defined relative humidities (RHs). Their water uptake and drug release were evaluated by differential scanning calorimetry/thermogravimetric analysis and dissolution studies, respectively. Analysis of the thermal behaviors of the drug/HPMC mixtures and of the polymer alone, as functions of RH, leads to the conclusion that most of the hydration water is retained by the polymer, and points to the occurrence of different types of hydration water, from the strongly polymer-bound water molecules at RH values up to 81%, to the almost âfree waterâ for RH values close to 100%. In addition, application of the Korsmeyer model to the dissolution results leads to the conclusion that the rate determining dissolution processes are predominantly of the fickian type.http://www.informaworld.com/10.1081/DDC-12001820
MFS transporters required for multidrug/multixenobiotic (MD/MX) resistance in the model yeast: understanding their physiological function through post-genomic approaches
Multidrug/Multixenobiotic resistance (MDR/MXR) is a widespread phenomenon with clinical, agricultural and biotechnological implications, where MDR/MXR transporters that are presumably able to catalyze the efflux of multiple cytotoxic compounds play a key role in the acquisition of resistance. However, although these proteins have been traditionally considered drug exporters, the physiological function of MDR/MXR transporters and the exact mechanism of their involvement in resistance to cytotoxic compounds are still open to debate. In fact, the wide range of structurally and functionally unrelated substrates that these transporters are presumably able to export has puzzled researchers for years. The discussion has now shifted towards the possibility of at least some MDR/MXR transporters exerting their effect as the result of a natural physiological role in the cell, rather than through the direct export of cytotoxic compounds, and the hypothesis that MDR/MXR transporters may have evolved in nature for other purposes than conferring chemoprotection has been gaining momentum in recent years. This review focuses on the drug transporters of the Major Facilitator Superfamily (MFS; drug:H+ antiporters) in the model yeast Saccharomyces cerevisiae. New insights into the natural roles of these transporters are described and discussed here, focusing on the knowledge obtained or suggested by post-genomic research. The new information reviewed here provides clues into the unexpectedly complex roles of these transporters, including a proposed indirect regulation of the stress response machinery and control of membrane potential and/or internal pH, with a special emphasis on a genome-wide view of the regulation and evolution of MDR/MXR-MFS transporters
Structures and Vibrational Spectra of CH,OCH,CH,OH : The
Ab initio calculations at the MP2/6-31G* and MP2/6-31G*//6-31G* levels have been carried out for the monomer
of 2-methoxyethanol (CH,OCH,CH,OH). The MP2/6-31G* results indicate that the two more stable conformers
(tGgâ and gGgâ) display intramolecular hydrogen bonds directed from the hydroxy H atom to one of the lone pairs
of the ether 0 atom, and that the tGgâ conformer is 6.3 kJ mol-â more stable than the gGgâ conformer. As the
MP2/6-31G* and MP2/6-3lG*//6-31G* calculations do not yield results differing by more than a few tenths of a kJ
mol-â, it is concluded that the structure-sensitive and the dynamic correlation corrections are far from being
additive. While the optimization of geometry for the correlated wavefunction generally leads to increase of bond
lengths and reduction of bond angles, on the whole the geometrical parameters undergo similar changes in
different conformers. Ab initio harmonic 6-31G* derived force fields were used to perform normal mode
analyses for the more stable conformers. The calculated v(CH) frequencies are found to correlate linearly with
some of the ab initio calculated CH bond lengths. An interpretation of the FTIR and Raman spectra for the liquid
phase consonant with the structural and vibrational ab initio results is presented. Two spectral features
observed both in Raman and in FTIR spectra and associated with v(0H) in monomeric species are ascribed to
conformers, in accord with the theoretical and experimental results. On the whole, both the structural and the
vibrational results presented point to a distinction between the hydrogen-bonded G-type conformers (tGgâ and
gGgâ) and the higher energy T-type conformers (tTg and tTt)
âRead That Articleâ: Exploring synergies between gaze and speech interaction
Gaze information has the potential to benefit Human-Computer Interaction (HCI) tasks, particularly when combined with speech. Gaze can improve our understanding of the user intention, as a secondary input modality, or it can be used as the main input modality by users with some level of permanent or temporary impairments. In this paper we describe a multimodal HCI system prototype which supports speech, gaze and the combination of both. The system has been developed for Active Assisted Living scenarios.info:eu-repo/semantics/acceptedVersio
Hydrogen-Bonded Dimers of CH3OCH2CH2OH: Ab Initio Structures and Multivariate Analysis
Structures and vibrational frequencies of relevant hydrogen-bonded dimers of 2-methoxyethanol are obtained
at the 3-21G*//Ah41 level (the 3-21G* basis set included polarization functions deliberately added to second
period atoms) and the results analyzed by standard multivariate methods. Dimers built from the same pair
of isolated monomers belong to the same homologous series. The most stable dimer is obtained from the
most stable conformations of both monomers, has a 10-membered intermolecular ring with a boat-chairboat
conformation, and presents a zero dipole moment. In addition, the most stable dimers of the three
homologous series have 10-membered rings with relatively symmetric conformations and zero or very low
dipole moments. The energies of the monomers in these dimers-monomers with geometries frozen in the
dimer-are close to the isolated and relaxed monomers energies. Generally speaking, OH 0 and CH 0
hydrogen bonds are found to contribute appreciably for the stability of the dimers. In particular, for the
second most stable dimer, two of the three CH -0 hydrogen bonds are shorter than the intramolecular OH- 0
bond for the isolated monomer. Multivariate analysis of all the results shows that the 0. *H-0 angle is
highly correlated with the H-0 bond length and that the COC and OCC angles are also highly correlated for
both monomers, hence confirming that each monomer in a dimer keeps essentially the same conformation it
has in the isolated monomer. The first and second principal components include all the highly correlated
variables and account for 45% of the total variance. 3-D plots of the three most important principal components
confirm a strong structural resemblance both for 10-membered ring dimers of homomeric series, Le., formed
by the same monomers, and for the more stable dimers in each homologous series. In addition, among the heteromeric dimers with seven membered rings, the ones whose first conformation is G or Gâ are less stable and located in a separate group
Germinabilidade e desprendimento do tegumento em melancia triploide submetida à escarificação mecùnica.
Suplemento. Edição dos Anais do 52 Congresso Brasileiro de Olericultura, Salvador, jul. 2012
Titration with automatic continuous positive airway pressure in obstructive sleep apnea
Background and objective
Autotitrating positive airway pressure (APAP) is an accepted titration method to determine the optimal positive airway pressure (PAP), for the treatment of obstructive sleep apnea (OSA). The required duration of APAP monitoring to determine a fixed continuous positive airway pressure level still remains to be established. We aimed to evaluate the variation in PAP level, delivered by APAP devices, at different periods of treatment, to determine the APAP treatment duration required to reach an effective and stable PAP level.
Methods
A cross-sectional study of 62 patients newly diagnosed with OSA were evaluated after 3 months of APAP therapy. APAP data corresponding to the first day (D1), first week (W1), seventh week (W7) and twelfth week (W12) under APAP therapy was collected. For the analysis of the pressure behaviour, the difference of P95th pressure level between W12 and W7 (P W12âW7), W12 and W1 (P W12âW1) and W12 and D1 (P W12âD1) was calculated.
Results
There was a high correlation in P95th pressure level between D1 and W12 (r = 0.771; p > 0.0001), W1 and W12 (r = 0.817; p > 0.0001), and W7 and W12 (r = 0.926; p > 0.0001). This correlation progressively increased with APAP use. A significance difference was found in concordance between P W12âW7 and P W12âD1 (p = 0.046) within the pressure range ±2 cmH2O. However there was no significant difference in concordance between P W12âW7 and P W12âW1.
Conclusions
One week of APAP therapy seems sufficient to determine an effective and stable PAP level, within the pressure range ±2 cmH2O.info:eu-repo/semantics/publishedVersio
DistĂșrbios do equilĂbrio electrolĂtico: estudo prospectivo no Hospital Prof. Dr. Fernando Fonseca
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