Publications

Abstract

This study sought to identify tumor characteristics that associate with regional lymph node metastases in squamous cell carcinomas originating in the upper gingiva.

Abstract

In English, Dutch, and other Germanic languages the initial phonological unit used in word production has been shown to be the phoneme; conversely, others have revealed that in Chinese this is the atonal syllable and in Japanese the mora. The current paper is, to our knowledge, the first to report chronometric data on Vietnamese phonological encoding. Vietnamese, a tonal language, is of interest as, despite its Austroasiatic roots, it has clear similarities with Chinese through extended contact over a prolonged period. Four experiments (i.e., masked priming, phonological Stroop, picture naming with written distractors, picture naming with auditory distractors) have been conducted to investigate Vietnamese phonological encoding. Results show that in all four experiments both onset effects as well as whole syllable effects emerge. This indicates that the fundamental phonological encoding unit during Vietnamese language production is the phoneme despite its apparent similarities to Chinese. This result might have emerged due to tone assignment being a qualitatively different process in Vietnamese compared to Chinese.

Abstract

For native (L1) English readers, masked presentations of past-tense verb primes (e.g., fell and looked) produce faster lexical decision latencies to their present-tense targets (e.g., FALL and LOOK) than orthographically related (e.g., fill and loose) or unrelated (e.g., master and bank) primes. This facilitation observed with morphologically related prime-target pairs (morphological priming) is generally taken as evidence for strong connections based on morphological relationships in the L1 lexicon. It is unclear, however, if similar, morphologically based, connections develop in non-native (L2) lexicons. Several earlier studies with L2 English readers have reported mixed results. The present experiments examine whether past-tense verb primes (both regular and irregular verbs) significantly facilitate target lexical decisions for Japanese-English bilinguals beyond any facilitation provided by prime-target orthographic similarity. Overall, past-tense verb primes facilitated lexical decisions to their present-tense targets relative to both orthographically related and unrelated primes. Replicating previous masked priming experiments with L2 readers, orthographically related primes also facilitated target recognition relative to unrelated primes, confirming that orthographic similarity facilitates L2 target recognition. The additional facilitation from past-tense verb primes beyond that provided by orthographic primes suggests that, in the L2 English lexicon, connections based on morphological relationships develop in a way that is similar to how they develop in the L1 English lexicon even though the connections and processing of lower level, lexical/orthographic information may differ. Further analyses involving L2 proficiency revealed that as L2 proficiency increased, orthographic facilitation was reduced, indicating that there is a decrease in the fuzziness in orthographic representations in the L2 lexicon with increased proficiency.

Abstract

We argue, based on a study of brain responses to speech sound differences in Japanese, that memory encoding of functional speech sounds-phonemes-are highly abstract. As an example, we provide evidence for a theory where the consonants/p t k b d g/ are not only made up of symbolic features but are underspecified with respect to voicing or laryngeal features, and that languages differ with respect to which feature value is underspecified. In a previous study we showed that voiced stops are underspecified in English [Hestvik, A., & Durvasula, K. (2016). Neurobiological evidence for voicing underspecification in English. Brain and Language], as shown by asymmetries in Mismatch Negativity responses to /t/ and /d/. In the current study, we test the prediction that the opposite asymmetry should be observed in Japanese, if voiceless stops are underspecified in that language. Our results confirm this prediction. This matches a linguistic architecture where phonemes are highly abstract and do not encode actual physical characteristics of the corresponding speech sounds, but rather different subsets of abstract distinctive features.

Abstract

Objectives: A new computer-aided screening system for osteoporosis using panoramic radiographs was developed. The conventional system could detect porotic changes within the lower border of the mandible, but its severity could not be evaluated. Our aim was to enable the system to measure severity by implementing a linear bone resorption severity index (BRSI) based on the cortical bone shape.
Methods: The participants were 68 females (>50 years) who underwent panoramic radiography and lumbar spine bone density measurements. The new system was designed to extract the lower border of the mandible as region of interests and convert them into morphological skeleton line images. The total perimeter length of the skeleton lines was defined as the BRSI. 40 images were visually evaluated for the presence of cortical bone porosity. The correlation between visual evaluation and BRSI of the participants, and the optimal threshold value of BRSI for new system were investigated through a receiver operator characteristic analysis. The diagnostic performance of the new system was evaluated by comparing the results from new system and lumbar bone density tests using 28 participants.
Results: BRSI and lumbar bone density showed a strong negative correlation (p < 0.01). BRSI showed a strong correlation with visual evaluation. The new system showed high diagnostic efficacy with sensitivity of 90.9%, specificity of 64.7%, and accuracy of 75.0%.
Conclusions: The new screening system is able to quantitatively evaluate mandibular cortical porosity. This allows for preventive screening for osteoporosis thereby enhancing clinical prospects.

Abstract

An ongoing debate in the speech production literature suggests that the initial building block to build up speech sounds differs between languages. That is, Germanic languages are suggested to use the phoneme, but Japanese and Chinese are proposed to use the mora or syllable, respectively. Several studies investigated this matter from a chronometric perspective (i.e., RTs and accuracy). However, a less attention has been paid to the actual acoustic utterances. The current study investigated the verbal responses of two Japanese-English bilingual groups of different proficiency levels (i.e., high and low) when naming English words and found that the presence or absence of vowel epenthesis depended on proficiency. The results indicate that: (1) English word pronunciation by low-proficient Japanese English bilinguals is likely based on their L1 (Japanese) building block and (2) that future studies would benefit from analyzing the acoustic data as well when making inferences from chronometric data.

Abstract

Previous studies suggest that bilinguals' lexical access is language non-selective, especially for orthographically identical translation equivalents across languages (i.e., identical cognates). The present study investigated how such words (e.g., meaning "school" in both Chinese and Japanese) are processed in the (late) Chinese - Japanese bilingual brain. Using an L2-Japanese lexical decision task, both behavioral and electrophysiological data were collected. Reaction times (RTs), as well as the N400 component, showed that cognates are more easily recognized than non-cognates. Additionally, an early component (i.e., the N250), potentially reflecting activation at the word-form level, was also found. Cognates elicited a more positive N250 than non-cognates in the frontal region, indicating that the cognate facilitation effect occurred at an early stage of word formation for languages with logographic scripts.

Abstract

In a masked priming word-naming task, a facilitation due to the initial-segmental sound overlap for 2-character kanji prime-target pairs was affected by certain orthographic properties (Yoshihara, Nakayama, Verdonschot, & Hino, 2017). That is, the facilitation that was due to the initial mora overlap occurred only when the mora was the whole pronunciation of their initial kanji characters (i.e., match pairs; e.g., /ka-se.ki/-/ka-rjo.ku/). When the shared initial mora was only a part of the kanji characters' readings, however, there was no facilitation (i.e., mismatch pairs; e.g., /ha.tu-a.N/-/ha.ku-bu.tu/). In the present study, we used a masked priming picture-naming task to investigate whether the previous results were relevant only when the orthography of targets is visually presented. In Experiment 1. the main findings of our word-naming task were fully replicated in a picture-naming task. In Experiments 2 and 3. the absence of facilitation for the mismatch pairs were confirmed with a new set of stimuli. On the other hand, a significant facilitation was observed for the match pairs that shared the 2 initial morae (in Experiment 4), which was again consistent with the results of our word-naming study. These results suggest that the orthographic properties constrain the phonological expression of masked priming for kanji words across 2 tasks that are likely to differ in how phonology is retrieved. Specifically, we propose that orthography of a word is activated online and constrains the phonological encoding processes in these tasks.

Abstract

Objectives: Metallic compounds present in the oral and maxillofacial regions (OMRs) cause large artefacts during MR scanning. We quantitatively assessed these artefacts embedded within a phantom according to standards set by the American Society for Testing and Materials (ASTM).
Methods: Seven metallic dental materials (each of which was a 10-mm(3) cube embedded within a phantom) were scanned [i.e. aluminium (Al), silver alloy (Ag), type IV gold alloy (Au), gold-palladium-silver alloy (Au-Pd-Ag), titanium (Ti), nickel-chromium alloy (NC) and cobalt-chromium alloy (CC)] and compared with a reference image. Sequences included gradient echo (GRE), fast spin echo (FSE), gradient recalled acquisition in steady state (GRASS), a spoiled GRASS (SPGR), a fast SPGR (FSPGR), fast imaging employing steady state (FIESTA) and echo planar imaging (EPI; axial/sagittal planes). Artefact areas were determined according to the ASTM-F2119 standard, and artefact volumes were assessed using OsiriX MD software (Pixmeo, Geneva, Switzerland).
Results: Tukey-Kramer post hoc tests were used for statistical comparisons. For most materials, scanning sequences eliciting artefact volumes in the following (ascending) order FSE-T-1/FSE-T-2 < FSPGR/SPGR < GRASS/GRE < FIESTA < EPI. For all scanning sequences, artefact volumes containing Au, Al, Ag and Au-Pd-Ag were significantly smaller than other materials (in which artefact volume size increased, respectively, from Ti < NC < CC). The artefact-specific shape (elicited by the cubic sample) depended on the scanning plane (i.e. a circular pattern for the axial plane and a "clover-like" pattern for the sagittal plane).
Conclusions: The availability of standardized information on artefact size and configuration during MRI will enhance diagnosis when faced with metallic compounds in the OMR.

Abstract

Purpose
To point out the advantages and drawbacks of high-dose rate brachytherapy in the treatment of mobile tongue cancer and indicate the clinical importance of modular lead-lined spacers when applying this technique to patients.
Methods
First, all basic steps to construct the modular spacer are shown. Second, we simulate and evaluate the dose rate reduction for a wide range of spacer configurations.
Results
With increasing distance to the source absorbed doses dropped considerably. Significantly more shielding was obtained when lead was added to the spacer and this effect was most pronounced on shorter (i.e. more clinically relevant) distances to the source.
Conclusions
The modular spacer represents an important addition to the planning and treatment stages of mobile tongue cancer using HDR-ISBT.

Abstract

Recent research has revealed that the way phonology is constructed during word production differs across languages. Dutch and English native speakers are suggested to incrementally insert phonemes into a metrical frame, whereas Mandarin Chinese speakers use syllables and Japanese speakers use a unit called the mora (often a CV cluster such as "ka" or "ki"). The present study is concerned with the question how bilinguals construct phonology in their L2 when the phonological unit size differs from the unit in their L1. Japanese English bilinguals of varying proficiency read aloud English words preceded by masked primes that overlapped in just the onset (e.g., bark-BENCH) or the onset plus vowel corresponding to the mora-sized unit (e.g., bell-BENCH). Low proficient Japanese English bilinguals showed CV priming but did not show onset priming, indicating that they use their L1 phonological unit when reading L2 English words. In contrast, high-proficient Japanese English bilinguals showed significant onset priming. The size of the onset priming effect was correlated with the length of time spent in English-speaking countries, which suggests that extensive exposure to L2 phonology may play a key role in the emergence of a language-specific phonological unit in L2 word production.

Abstract

Person names and common nouns differ in how they are stored in the mental lexicon. Using event-related potentials, this study compared the integration of names and nouns into sentence contexts. Both person names and common nouns were highly related in meaning and either congruent or incongruent within the previous contexts. Name incongruence elicited an N400 effect, suggesting that people were able to rapidly retrieve the semantic meaning of names from long-term memory even when this process was mediated by person identification. Conversely, participants showed a “good enough” processing of the nouns due to their low specificity level and, thus, rich semantic associations, leading to a P600 effect. These distinctive ERP effects provide clear evidence for the distinctive semantic representations of these word categories by showing that the activation of a name’s meaning is mediated by a single connection between identity-specific information and person identity, whereas multiple connections exist between nouns and their meanings.