750 research outputs found

    Korean laryngeal contrast revisited:An electroglottographic study on denasalized and oral stops

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    In several Korean dialects, domain-initial nasal onsets undergo denasalization as a recent sound change. Nasal stops may be realized as prevoiced or even devoiced stops. This makes it necessary to examine the interplay of phonetic properties of the denasalized and the three oral stop series as a whole, in synchrony and diachrony. What are their concomitant and conflicting properties? Our study provides a bigger picture of the laryngeal contrast in Seoul and Gyeonggi Korean by examining the acoustic distributions related to the laryngeal properties of the four stop series, using acoustic and electroglottographic data. VOT and 'f'0 play important roles in the distinction of the four stop series, in line with previous studies. While the contribution of voice quality is relatively minor, we show that it plays an essential role of disambiguation when the VOT–'f'0 space gets crowded: When lenis stops can be confused with other stops, there is an enhancement of breathy voice. Finally, we discuss stop variation according to prosodic contexts. We highlight the basis of both syntagmatic variation and paradigmatic contrast in their phonetic implementations. They illustrate a constant reorganization to reconcile contrast maintenance with constraints from articulatory and perceptual systems, as well as language-specific structures

    VOT-F0 coarticulation in Japanese:Production-biased or misparsing?

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    International audienceIn production, word-initial voicing contrast of plosives in Tokyo Japanese is not robustly based on VOT, since young speakers tend to devoice previously voiced plosives. Meanwhile, speakers rely heavily on f0. The present study aims to examine the role of VOT and f0 cues in perception. We conducted an identification test using resynthesized stimuli along a VOT continuum (-60 to +40 ms) orthogonal to an f0 continuum. Results suggested a categorical perception of VOT, while f0 was especially useful when VOT was around 0 ms. Higher f0 contours affected the response rate more than lower f0 contours, suggesting that the perceptual role of f0 raising was more important than f0 lowering. Hence, plosive devoicing in production is not preceded by listeners' misparsing of low f0 and prevoicing. Their misattribution of high f0 to voicelessness may play a more important role in the shift of VOT-f0 cue weighting in perception and production

    Sociolinguistic motivations in sound change: on-going loss of low tone breathy voice in Shanghai Chinese

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    This study focuses on the on-going disappearance of low tone breathiness in Shanghai Chinese. In the change from a voicing contrast to a tone register contrast in Sinitic languages, the ancient voiced series was characterised by a breathy voice quality, which remained as a secondary and redundant cue of low tones in Shanghai Chinese. This study, using transversal production data from 12 young and 10 elderly speakers, shows that low tone breathiness is better preserved by elderly than young speakers, and by male than female speakers. We predict a future loss of this secondary cue, which is speeding up due to the interference with Standard Chinese. We also found that the disappearance is more advanced in female speakers, which might be explained by female speakers’ stronger adherence to Standard Chinese as the prestigious form. Indeed, our young female speakers reported more frequent usage of Standard Chinese than Shanghai Chinese and higher competence in Standard Chinese than in Shanghai Chinese, whereas young male speakers were more confident in their usage of Shanghai Chinese

    Estimating CT Image From MRI Data Using Structured Random Forest and Auto-Context Model

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    Computed tomography (CT) imaging is an essential tool in various clinical diagnoses and radiotherapy treatment planning. Since CT image intensities are directly related to positron emission tomography (PET) attenuation coefficients, they are indispensable for attenuation correction (AC) of the PET images. However, due to the relatively high dose of radiation exposure in CT scan, it is advised to limit the acquisition of CT images. In addition, in the new PET and magnetic resonance (MR) imaging scanner, only MR images are available, which are unfortunately not directly applicable to AC. These issues greatly motivate the development of methods for reliable estimate of CT image from its corresponding MR image of the same subject. In this paper, we propose a learning-based method to tackle this challenging problem. Specifically, we first partition a given MR image into a set of patches. Then, for each patch, we use the structured random forest to directly predict a CT patch as a structured output, where a new ensemble model is also used to ensure the robust prediction. Image features are innovatively crafted to achieve multi-level sensitivity, with spatial information integrated through only rigid-body alignment to help avoiding the error-prone inter-subject deformable registration. Moreover, we use an auto-context model to iteratively refine the prediction. Finally, we combine all of the predicted CT patches to obtain the final prediction for the given MR image. We demonstrate the efficacy of our method on two datasets: human brain and prostate images. Experimental results show that our method can accurately predict CT images in various scenarios, even for the images undergoing large shape variation, and also outperforms two state-of-the-art methods

    The effect of calcium phosphate nanoparticles on hormone production and apoptosis in human granulosa cells

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    <p>Abstract</p> <p>Objectives</p> <p>Although many nanomaterials are being used in academia, industry and daily life, there is little understanding about the effects of nanoparticles on the reproductive health of vertebral animals, including human beings. An experimental study was therefore performed here to explore the effect of calcium phosphate nanoparticles on both steroid hormone production and apoptosis in human ovarian granulosa cells.</p> <p>Methods</p> <p>Calcium phosphate nanoparticles uptaking was evaluated by transmission electron microscopy (TEM). The cell cycle was assessed with propidium iodide-stained cells (distribution of cells in G0/G1, S, and G2/M phases) by flow cytometry. The pattern of cell death (necrosis and apoptosis) was analyzed by flow cytometry with annexin V-FITC/PI staining. The expression of mRNAs encoding P450scc, P450arom and StAR were determined by RT-PCR. Progesterone and estradiol levels were measured by radioimmunoassay.</p> <p>Results</p> <p>TEM results confirmed that calcium phosphate nanoparticles could enter into granulosa cells, and distributed in the membranate compartments, including lysosome and mitochondria and intracellular vesicles. The increased percentage of cells in S phase when cultured with nanoparticles indicated that there was an arrest at the checkpoint from phase S-to-G2/M (from 6.28 +/- 1.55% to 11.18 +/- 1.73%, p < 0.05). The increased ratio of S/(G2/M) implied the inhibition of DNA synthesis and/or impairment in the transition of the S progression stage. The apoptosis rate of normal granulosa cells was 7.83 +/- 2.67%, the apoptotic rate increased to 16.53 +/- 5.56% (P < 0.05) after the cells were treated with 100 microM calcium phosphate nanoparticles for 48 hours. Treatment with calcium phosphate nanoparticles at concentrations of 10-100 microM didn't significantly change either the progesterone or estradiol levels in culture fluid, and the expression levels of mRNAs encoding P450scc, P450arom and StAR after 48 h and 72 h period of treatment.</p> <p>Conclusion</p> <p>Calcium phosphate nanoparticles interfered with cell cycle of cultured human ovarian granulosa cells thus increasing cell apoptosis. This pilot study suggested that effects of nanoparticles on ovarian function should be extensively investigated.</p

    Dose-related liver injury of Geniposide associated with the alteration in bile acid synthesis and transportation.

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    Fructus Gardenia (FG), containing the major active constituent Geniposide, is widely used in China for medicinal purposes. Currently, clinical reports of FG toxicity have not been published, however, animal studies have shown FG or Geniposide can cause hepatotoxicity in rats. We investigated Geniposide-induced hepatic injury in male Sprague-Dawley rats after 3-day intragastric administration of 100 mg/kg or 300 mg/kg Geniposide. Changes in hepatic histomorphology, serum liver enzyme, serum and hepatic bile acid profiles, and hepatic bile acid synthesis and transportation gene expression were measured. The 300 mg/kg Geniposide caused liver injury evidenced by pathological changes and increases in serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and γ-glutamytransferase (γ-GT). While liver, but not sera, total bile acids (TBAs) were increased 75% by this dose, dominated by increases in taurine-conjugated bile acids (t-CBAs). The 300 mg/kg Geniposide also down-regulated expression of Farnesoid X receptor (FXR), small heterodimer partner (SHP) and bile salt export pump (BSEP). In conclusion, 300 mg/kg Geniposide can induce liver injury with associated changes in bile acid regulating genes, leading to an accumulation of taurine conjugates in the rat liver. Taurocholic acid (TCA), taurochenodeoxycholic acid (TCDCA) as well as tauro-α-muricholic acid (T-α-MCA) are potential markers for Geniposide-induced hepatic damage

    Le corpus PhoDiFLE : un corpus commun de français langue étrangère pour une étude phonétique des productions de locuteurs de langues maternelles plurielles

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    PhoDiFLE est un corpus créé pour permettre la comparaison entre des productions phonétiques de français natifs et d’apprenants, à des fins didactiques. Nous présentons ici les questionnements qui ont guidé notre réflexion dans la réalisation de ce corpus. À travers une démarche mixte (guidée par corpus et fondée sur corpus), nous nous intéressons aux écarts de réalisations avec la « norme », selon l’origine des locuteurs. Des analyses acoustiques et perceptives conduisent à la création d’outils intégrés de formalisation, de représentation, de remédiation et d’évaluation selon la langue d’origine de chaque apprenant.The PhoDiFLE corpus has been developed to enable researchers, especially those concerned with remedial phonetics, to compare French native speakers and foreign learners utterances in French. This article examines the issues that had to be dealt with while creating this corpus. Our approach combines corpus-driven and corpus-based studies and focuses on the phonetic variants across native and non-native speakers. Acoustic and perceptual analyses allow to compare their productions. This corpus will finally result in the making of tools aiming to formalise, represent, correct and assess the variants observed in learners of French as a Second Language

    FTO Knockout Causes Chromosome Instability and G2/M Arrest in Mouse GC-1 Cells

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    N6-methyladenosine (m6A) is the most abundant modification on eukaryotic mRNA. m6A plays important roles in the regulation of post-transcriptional RNA splicing, translation, and degradation. Increasing studies have uncovered the significance of m6A in various biological processes such as stem cell fate determination, carcinogenesis, adipogenesis, stress response, etc, which put forwards a novel conception called epitranscriptome. However, functions of the fat mass and obesity-associated protein (FTO), the first characterized m6A demethylase, in spermatogenesis remains obscure. Here we reported that depletion of FTO by CRISPR/Cas9 induces chromosome instability and G2/M arrest in mouse spermatogonia, which was partially rescued by expression of wild type FTO but not demethylase inactivated FTO. FTO depletion significantly decreased the expression of mitotic checkpoint complex and G2/M regulators. We further demonstrated that the m6A modification on Mad1, Mad2, Bub1b, Cdk1, and Ccnb2 were directly targeted by FTO. Therefore, FTO regulates cell cycle and mitosis checkpoint in spermatogonia because of its m6A demethylase activity. The findings give novel insights into the role of RNA methylation in spermatogenesis
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