6,252 research outputs found
Contributions of the high-RMS-level segments to the intelligibility of mandarin sentences
Recent evidence suggests that segments carrying more spectral changes [e.g., consonant-vowel boundaries in the middle root-mean-square (RMS) level segments] are important to predict the intelligibility of English sentences. Nevertheless, considering the difference between Mandarin and English languages, it is hypothesized that the high-RMS-level segments might provide more perceptual information to the intelligibility of Mandarin speech. Two studies were conducted in this paper to assess the relative contributions of the high-RMS-level segments to the intelligibility of Mandarin sentences, i.e., speech perception and intelligibility prediction. Results show that 1) Mandarin sentences containing the high-RMS-level (i.e., above the overall RMS level of the whole utterance) segments are more intelligible (i.e., recognition rate up to 91%) than those with the middle-RMS-level segments; and 2) the high-RMS-level segments, which carry more vowel and tonal information, contribute more in predicting the intelligibility of Mandarin sentences in noise.published_or_final_versio
Assessing the perceptual contributions of vowels and consonants to Mandarin sentence intelligibility
published_or_final_versio
Consonant discrimination by Mandarin-speaking children with prelingual hearing impairment
postprin
Are autistic traits measured equivalently in individuals with and without an Autism Spectrum Disorder?:An invariance analysis of the Autism Spectrum Quotient Short Form
It is common to administer measures of autistic traits to those without autism spectrum disorders (ASDs) with, for example, the aim of understanding autistic personality characteristics in non-autistic individuals. Little research has examined the extent to which measures of autistic traits actually measure the same traits in the same way across those with and without an ASD. We addressed this question using a multi-group confirmatory factor invariance analysis of the Autism Quotient Short Form (AQ-S: Hoekstra et al. in J Autism Dev Disord 41(5):589-596, 2011) across those with (n = 148) and without (n = 168) ASD. Metric variance (equality of factor loadings), but not scalar invariance (equality of thresholds), held suggesting that the AQ-S measures the same latent traits in both groups, but with a bias in the manner in which trait levels are estimated. We, therefore, argue that the AQ-S can be used to investigate possible causes and consequences of autistic traits in both groups separately, but caution is due when combining or comparing levels of autistic traits across the two group
Structure and Transport in Coatings from Multiscale Computed Tomography of Coatings-New Perspectives for Eelectrochemical Impedance Spectroscopy Modeling?
Computed Tomography (CT) is an approach that has been extensively applied in many areas of science from understanding structures in living organisms to materials science. In materials science, the study of structures within coatings presents challenges on at least two different levels. First, the structure of the coatings needs to be understood from the atomic scale, where dissolution reactions begin, up to length scales which cover the aggregation of inhibitors and other additives, which take place at ∼10−5 m, i.e. 4 to 5 orders of magnitude. CT is a favourable imaging technique since it allows multiscale information to be obtained non-destructively down to tens of nanometres. In this study X-ray absorption contrast imaging has been used to examine structures created using strontium chromate (SrCrO4) particles embedded in an epoxy film. It has been found that SrCrO4 particles can form clusters that extend a few hundred microns in the plane of the film, span the thickness of the film and have fractal characteristics. There are also volumes of low density epoxy of similar sizes and characteristics to the SrCrO4 clusters. The SrCrO4 clusters have a strong influence on the leaching behaviour since the release changes with time. Initially, leaching is controlled by direct dissolution but, as the clusters dissolve, the release is dominated by the fractal dimension of the cluster. The dissolved clusters leave behind voids filled with electrolyte that provide alternative transport pathways for corrosive ions through the polymer. In this paper, the nature of these clusters will be reviewed and the implication for transport properties and electrochemical assessment will be explored
Paradoxical roles of antioxidant enzymes:Basic mechanisms and health implications
Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are generated from aerobic metabolism, as a result of accidental electron leakage as well as regulated enzymatic processes. Because ROS/RNS can induce oxidative injury and act in redox signaling, enzymes metabolizing them will inherently promote either health or disease, depending on the physiological context. It is thus misleading to consider conventionally called antioxidant enzymes to be largely, if not exclusively, health protective. Because such a notion is nonetheless common, we herein attempt to rationalize why this simplistic view should be avoided. First we give an updated summary of physiological phenotypes triggered in mouse models of overexpression or knockout of major antioxidant enzymes. Subsequently, we focus on a series of striking cases that demonstrate “paradoxical” outcomes, i.e., increased fitness upon deletion of antioxidant enzymes or disease triggered by their overexpression. We elaborate mechanisms by which these phenotypes are mediated via chemical, biological, and metabolic interactions of the antioxidant enzymes with their substrates, downstream events, and cellular context. Furthermore, we propose that novel treatments of antioxidant enzyme-related human diseases may be enabled by deliberate targeting of dual roles of the pertaining enzymes. We also discuss the potential of “antioxidant” nutrients and phytochemicals, via regulating the expression or function of antioxidant enzymes, in preventing, treating, or aggravating chronic diseases. We conclude that “paradoxical” roles of antioxidant enzymes in physiology, health, and disease derive from sophisticated molecular mechanisms of redox biology and metabolic homeostasis. Simply viewing antioxidant enzymes as always being beneficial is not only conceptually misleading but also clinically hazardous if such notions underpin medical treatment protocols based on modulation of redox pathways
Morphological and Bactericidal Effects of Different Antibiotics on Helicobacter pylori
Background: Helicobacter pylori (H. pylori) is a spiral Gram negative bacteria that can transform to the coccoid form in adverse conditions.
Objectives: The aim of this study was to determine the in vitro morphological and bactericidal effects of metronidazole, amoxicillin and
clarithromycin on H. pylori.
Materials and Methods: The standard strain 26695 of H. pylori was cultured on Brucella agar (BA) and the minimum inhibitory
concentrations (MICs) of three antibiotics were determined by E-test method. The bacteria were exposed to antibiotics at 1/2 MIC, MIC and
2X MIC concentrations in Brucella broth (BB). Induced coccoid forms were confirmed by Gram staining and light microscopy. The viability
of cells as well as the susceptibility of viable coccoids to antibiotics were examined using the flow cytometry method.
Results: All of the three antibiotics at sub-MIC induced coccoid forms. The highest rates of coccoids (> 90%) were induced at 0.008 μg/
mL concentration (1/2 MIC) of amoxicillin, 72 hours postexposure. Metronidazole and clarithromycin with 1/2 MIC (0.5 and 0.125 µg/mL
respectively) induced lower rates of coccoid forms (60% and 40% respectively). Potent bactericidal effects on coccoids were observed with
Metronidazole at 2X MIC and clarithromycin at MIC (0.25 µg/mL) (80 - 90%). Amoxicillin with MIC and 2X MIC had no bactericidal effect on
coccoid forms.
Conclusions: Despite the good in vitro bactericidal effect of amoxicillin on spiral forms of H. pylori, this antibiotic has little effect on
induced coccoids that may develop after the inappropriate in vivo antibacterial treatment. Hence, for successful therapy, it is essential not
only to eradicate the spiral forms, but to eliminate the viable coccoids
Bifactor analysis of motivation for charity sport event participation
The purpose of this study was to examine the utility of the existing subscales of charity sport events (CSEs) participation motivation by adopting both a second-order modeling and a bifactor modeling approaches. The results with 488 college students revealed that the bifactor model provided a better interpretation of the data compared to second-order model. The five-factor CSE motivation significantly predict the intention to participate in CSEs along with two domain-specific motivations, namely ‘sport and event’ and ‘cause’ while other three domain-specific motivations including ‘philanthropic’, ‘social interaction’, and ‘reference group’ are not statistically significant predictors. The results suggest that the bifactor model is more useful in predicting this group’s participation in charity sport events. © 2015, Springer-Verlag Berlin Heidelberg
Preclinical activity of gefitinib in non-keratinizing nasopharyngeal carcinoma cell lines and biomarkers of response
This study evaluated the preclinical activity and molecular predictors of response to gefitinib (Iressa®, Astra Zeneca Inc, UK) in nasopharyngeal carcinoma (NPC). The activity of gefitinib was evaluated in four human NPC cell lines-HK1, HONE-1, CNE2, C666-1. A representative gefitinib-sensitive (HK1, IC50 = 250 nM) and gefitinib-resistant cell line (HONE-1, IC 50 > 15 μM) were selected and compared for expression of epidermal growth factor receptor (EGFR) and related ligands, and activation of downstream proteins. Gefitinib induced G1 cycle arrest, apoptosis and inhibited cell invasion more significantly in HK1 than HONE-1 cells. HK1 expressed higher levels of p-EGFR, lower p-AKT and phospho-signal transducer and activator of transcription 3 (p-STAT3) than other cell lines. EGFR gene was found to be amplified in HK1. Gefitinib at IC50 concentrations significantly suppressed EGF-induced activation of p-EGFR, phospho-mitogen-activated protein kinase (p-MAPK) and p-STAT3, but p-AKT showed persistent activation in HK1 and HONE-1 cells. There was no difference in EGFR-ligand expression between the 4 NPC cell lines. In NPC samples derived from non-responders to gefitinib, 50% and 60% showed cytoplasmic and nuclear pi-EGFR expression, respectively, and 33% showed p-AKT expression. EGFR or KRAS mutations were not detected. This study suggests that most NPC cell lines are intrinsically resistant to gefitinib (except HK1 cells), and further studies are needed to confirm whether EGFR gene amplification and persistent AKT activation may influence response to gefitinib in NPC. © 2009 Springer Science+Business Media, LLC.published_or_final_versionSpringer Open Choice, 01 Dec 201
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