Publications

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.

Abstract

This chapter describes how speakers access words from the mental lexicon. Lexical access is a crucial
component in the process of transforming thoughts into speech. Some theories consider lexical access to be
strictly serial and discrete, while others view this process as being cascading or even interactive, i.e. the different
sub-levels influence each other. We discuss some of the evidence in favour and against these viewpoints, and
also present arguments regarding the ongoing debate on how words are selected for production. Another important
issue concerns the access to morphologically complex words such as derived and inflected words, as well as
compounds. Are these accessed as whole entities from the mental lexicon or are the parts assembled online? This
chapter tries to provide an answer to that question as well.

Abstract

Recent research has put forward the idea that Chinese speech production is governed by the syllable as the fundamental phonological unit. However, it may be that onset priming might be more difficult to obtain in Mandarin Chinese. Therefore, in this study, the degree of overlap between prime and target was increased from C to CV (i.e., extending beyond the phoneme) as well as whether primes and targets had an overlapping structure (CV vs. CVN). Subsyllabic priming effects were found (i.e., onset + vowel overlap but not purely onset overlap), contrasting with the claim that the syllable is the compulsory building block in the initial construction of Mandarin Chinese phonology.

Abstract

The Microsoft KINECT is a 3D sensing device originally developed for the XBOX. The Microsoft KINECT opens up many exciting new opportunities for conducting experimental research on human behavior. We investigated some of these possibilities within the field of psycholinguistics (specifically: language production) by creating software, using C#, allowing for the KINECT to be used in a typical psycholinguistic experimental setting. The results of a naming experiment using this software confirmed that the KINECT was able to measure the effects of a robust psycholinguistic variable (word frequency) on naming latencies. However, although the current version of the software is able to measure psycholinguistic variables of interest, we also discuss several points where the software can still stand to be improved. The main aim of this paper is to make the software freely available for assessment and use by the psycholinguistic community and to illustrate the KINECT as a potentially valuable tool for investigating human behavior, especially in the field of psycholinguistics.

Abstract

The process of reading aloud bare nouns in alphabetic languages is immune to semantic context effects from pictures. This is accounted for by assuming that words in alphabetic languages can be read aloud relatively fast through a sub-lexical grapheme-phoneme conversion (GPC) route or by a direct route from orthography to word form. We examined semantic context effects in a word-naming task in two languages with logographic scripts for which GPC cannot be applied: Japanese kanji and Chinese hanzi. We showed that reading aloud bare nouns is sensitive to semantically related context pictures in Japanese, but not in Chinese. The difference between these two languages is attributed to processing costs caused by multiple pronunciations for Japanese kanji. (C) 2010 Elsevier B.V. All rights reserved.