Does Native Language Matter in Perceptual Ratings of Dysarthria?

PURPOSE: Despite the general agreement that dysarthria characteristics are largely language-independent, few efforts have attempted a systematic comparison across languages. To examine the role of native languages in the perception of speech characteristics of dysarthria secondary to Parkinson's disease (PD), auditory-perceptual ratings of dysarthria, and confidence level of the judgments were compared between two listener groups: language-matched and language-crossed. METHOD: A total of 60 listeners (35 native speakers of Korean and 25 native speakers of American English) estimated speech abnormality for 20 speech dimensions using a visual analog scale method for both language-matched and language-crossed speech stimuli. Speech stimuli were passage readings of the respective languages obtained from individuals with and without PD. RESULTS: For speech dimension ratings, eight of 20 speech dimensions revealed significant differences in response to PD speech between the two listener groups, for most of which, language-crossed listeners' estimation was lower (i.e., more impaired) than language-matched listeners. For confidence-level ratings, language-matched listeners were less confident in the ratings of speakers with PD compared to the language-crossed listeners. CONCLUSIONS: The data support both language-universal and language-specific aspects in perceiving dysarthria characteristics, such that native language plays a role, especially when rating articulatory- and rhythmic-related characteristics. The findings are discussed with respect to the role of linguistic information, such as phonetic inventories and prosodic structures, in perceiving dysarthria characteristics.

A single pair of pharyngeal neurons functions as a commander to reject high salt in Drosophila melanogaster.

Salt (NaCl), is an essential nutrient for survival, while excessive salt can be detrimental. In the fruit fly, Drosophila melanogaster, internal taste organs in the pharynx are critical gatekeepers impacting the decision to accept or reject a food. Currently, our understanding of the mechanism through which pharyngeal gustatory receptor neurons (GRNs) sense high salt are rudimentary. Here, we found that a member of the ionotropic receptor family, Ir60b, is expressed exclusively in a pair of GRNs activated by high salt. Using a two-way choice assay (DrosoX) to measure ingestion volume, we demonstrate that IR60b and two co-receptors IR25a and IR76b are required to prevent high salt consumption. Mutants lacking external taste organs but retaining the internal taste organs in the pharynx exhibit much higher salt avoidance than flies with all taste organs but missing the three IRs. Our findings highlight the vital role for IRs in a pharyngeal GRN to control ingestion of high salt.

Effects of Deep-Brain Stimulation on Speech: Perceptual and Acoustic Data.

PURPOSE: This study examined speech changes induced by deep-brain stimulation (DBS) in speakers with Parkinson's disease (PD) using a set of auditory-perceptual and acoustic measures. METHOD: Speech recordings from nine speakers with PD and DBS were compared between DBS-On and DBS-Off conditions using auditory-perceptual and acoustic analyses. Auditory-perceptual ratings included voice quality, articulation precision, prosody, speech intelligibility, and listening effort obtained from 44 listeners. Acoustic measures were made for voicing proportion, second formant frequency slope, vowel dispersion, articulation rate, and range of fundamental frequency and intensity. RESULTS: No significant changes were found between DBS-On and DBS-Off for the five perceptual ratings. Four of six acoustic measures revealed significant differences between the two conditions. While articulation rate and acoustic vowel dispersion increased, voicing proportion and intensity range decreased from the DBS-Off to DBS-On condition. However, a visual examination of the data indicated that the statistical significance was mostly driven by a small number of participants, while the majority did not show a consistent pattern of such changes. CONCLUSIONS: Our data, in general, indicate no-to-minimal changes in speech production ensued from DBS stimulation. The findings are discussed with a focus on large interspeaker variability in PD in terms of their speech characteristics and the potential effects of DBS on speech.

A single pair of pharyngeal neurons functions as a commander to reject high salt in Drosophila melanogaster.

Salt is an essential nutrient for survival, while excessive NaCl can be detrimental. In the fruit fly, Drosophila melanogaster, internal taste organs in the pharynx are critical gatekeepers impacting the decision to accept or reject a food. Currently, our understanding of the mechanism through which pharyngeal gustatory receptor neurons (GRNs) sense high salt are rudimentary. Here, we found that a member of the ionotropic receptor family, Ir60b, is expressed exclusively in a pair of GRNs activated by high salt. Using a two-way choice assay (DrosoX) to measure ingestion volume, we demonstrate that IR60b and two coreceptors IR25a and IR76b, are required to prevent high salt consumption. Mutants lacking external taste organs but retaining the internal taste organs in the pharynx exhibit much higher salt avoidance than flies with all taste organs but missing the three IRs. Our findings highlight the vital role for IRs in a pharyngeal GRN to control ingestion of high salt.

Raising Awareness About Language- and Culture-Specific Considerations in the Management of Dysarthria Associated With Parkinson's Disease Within the United States.

PURPOSE: The purpose of this article is to raise awareness about the importance of diverting from English-centric approaches in the management of dysarthria associated with Parkinson's disease (PD) in the United States, and embracing a language- and culture-specific perspective when working with linguistically and culturally diverse populations within the context of culturally responsive, precision medicine. METHOD: This tutorial is divided into two primary components: a critical review of language universal and language-specific characteristics of dysarthria associated with PD and their relationship with speech intelligibility, and a practical guide to culturally responsive evidence-based practice for speech-language pathologists. CONCLUSIONS: We offer a framework for linguistically and culturally appropriate considerations when working with clients with dysarthria associated with PD. While "universal" representations of dysarthria may be part of the big picture, language-specific contributions to speakers' intelligibility should be carefully examined to maximize treatment outcomes. Additionally, an evidence-based model that fully embraces clients' wishes and values within the context of culturally responsive, precision medicine should be prioritized, a practice that may include the use of interpreters.

Identification of gallbladder cancer by direct near-infrared measurement of deuterated chloroform-extracted organic phase from human bile.

A simple near-infrared (NIR) spectroscopic scheme enabling direct measurement of organic phase extracted from human bile with no spectral interference from the extraction solvent was demonstrated for identification of gallbladder (GB) cancer. This scheme is used to recognize the different lipid contents in bile samples from GB cancer patients using NIR spectroscopy for disease identification. To this end, the extraction solvent should provide an absorption-free NIR region to observe peaks of related metabolite. For this purpose, deuterated chloroform (CDCl3) is uniquely suited as an extraction medium because it has few absorption peaks in the 4380-4100 cm-1 range, where intense peaks for lipids and cholesterol are located. This exploratory study used 37 bile samples (obtained from five normal subjects and nine GB polyp, 11 gallstone, six hepatocellular carcinoma (HCC), and six GB cancer patients). The transmission NIR spectra of the organic phases extracted using CDCl3 in a commercial glass vial were directly measured. The peak intensities of the GB cancer samples were lower than those of the other samples, and the differences were statistically significant, with a confidence interval greater than 99.0%. The lower lipid and cholesterol contents in the organic phases of the GB cancer samples were effectively identified in the corresponding NIR spectra. Therefore, the proposed NIR scheme is simpler and faster than the previous infrared (IR) measurement approach that requires solvent drying to highlight the buried metabolite peaks under a solvent absorption band.

Vowel Acoustics as Predictors of Speech Intelligibility in Dysarthria.

PURPOSE: This study sought to determine if alternative vowel space area (VSA) measures (i.e., novel trajectory-based measures: vowel space hull area and vowel space density) predicted speech intelligibility to the same extent as two traditional vowel measures (i.e., token-based measures: VSA and corner dispersion) in speakers with dysarthria. Additionally, this study examined if the strength of the relationship between acoustic vowel measures and intelligibility differed based on how intelligibility was measured (i.e., orthographic transcriptions [OTs] and visual analog scale [VAS] ratings). METHOD: The Grandfather Passage was read aloud by 40 speakers with dysarthria of varying etiologies, including Parkinson's disease (n = 10), amyotrophic lateral sclerosis (n = 10), Huntington's disease (n = 10), and cerebellar ataxia (n = 10). Token- and trajectory-based acoustic vowel measures were calculated from the passage. Naïve listeners (N = 140) were recruited via crowdsourcing to provide OTs and VAS intelligibility ratings. Hierarchical linear regression models were created to model OTs and VAS intelligibility ratings using the acoustic vowel measures as predictors. RESULTS: Traditional VSA was the sole significant predictor of speech intelligibility for both the OTs (R 2 = .259) and VAS (R 2 = .236) models. In contrast, the trajectory-based measures were not significant predictors of intelligibility. Additionally, the OTs and VAS intelligibility ratings conveyed similar information. CONCLUSIONS: The findings suggest that traditional token-based vowel measures better predict intelligibility than trajectory-based measures. Additionally, the findings suggest that VAS methods are comparable to OT methods for estimating speech intelligibility for research purposes.

The Effects of Deep Brain Stimulation on Speech Motor Control in People With Parkinson's Disease.

PURPOSE: Despite the overall benefits of deep brain stimulation (DBS) in Parkinson's disease (PD), its effects on speech production have been mixed when examined using auditory-perceptual and acoustic measures. This study investigated the effects of DBS on the lip and jaw kinematics during sentence production in individuals with dysarthria secondary to PD. METHOD: Twenty-seven participants from three groups were included in the study: (a) individuals with PD and without DBS (PD group), (b) individuals with PD and with DBS (PD-DBS group), and (c) neurologically healthy control speakers (HC group). Lip and jaw movements during speech were recorded using optical motion capture and analyzed for path distance, speed, duration, articulatory stability, and interarticulator coordination. RESULTS: The PD-DBS group showed (a) increased path distance compared with the PD and HC groups and (b) increased speed compared with the PD group but not the HC group. Both PD and PD-DBS groups exhibited lengthened sentence duration compared with the HC group. Articulatory stability was greater for the two PD groups, PD and PD-DBS, compared with the HC group. Spatial, but not temporal, coordination was lower for the PD group than for the other two groups. The only kinematic changes between the DBS on and off conditions within the PD-DBS group were increases in spatial coordination. CONCLUSIONS: These data suggest that DBS primarily affects the amplitude scaling of articulatory movements, but not the temporal scaling, in individuals with PD. The findings are discussed with respect to the DBS-induced neural changes and their effects on speech motor control in PD.

Feasibility of diffuser-incorporated near-infrared trans-reflectance measurement for quantitative detection of microplastics captured in perfluorocarbon.

A diffuser-incorporated near-infrared (NIR) trans-reflectance measurement is demonstrated for quantitative detection of polyethylene (PE) particles captured in perfluorohexane (PFH, C6F14). PFH effectively captures PE particles through its hydrophobicity and absorbs little NIR radiation, recommending it for use in background-free NIR detection of captured PE particles. A reflective metal disk was used to push the captured PE particles in PFH toward the bottom of the vial that contained the sample, and the trans-reflectance measurement was performed by illuminating NIR radiation from the bottom of the vial at 45o. Reproducibility is limited by the variation in the positions of small PE-particle aggregates at the water/PFH interface and the difficulty in ensuring full NIR sampling (coverage) of large aggregates. An effective way to secure improved reproducibility under these circumstances is illumination of broader and more uniform NIR radiation for measurement. For this purpose, a polytetrafluoroethylene (PTFE) disk was uniquely incorporated as a diffuser for the trans-reflectance measurement. Compared to the measurement with no diffuser, the diffuser-incorporated scheme produced more distinct PE peaks of low-quantity samples (0.1 and 0.2 mg) and enhanced the reproducibility in measurements of all the samples (0.1-4.0 mg of PE). As a result, the correlation between peak intensity and particle quantity was excellent (R2: 0.997), and a limit of detection of 0.07 mg was achieved.

An Acoustic-Phonetic Approach to Effects of Face Masks on Speech Intelligibility.

PURPOSE: This study aimed to examine the effects of wearing a face mask on speech acoustics and intelligibility, using an acoustic-phonetic analysis of speech. In addition, the effects of speakers' behavioral modification while wearing a mask were examined. METHOD: Fourteen female adults were asked to read a set of words and sentences under three conditions: (a) conversational, mask-off; (b) conversational, mask-on; and (c) clear, mask-on. Seventy listeners rated speech intelligibility using two methods: orthographic transcription and visual analog scale (VAS). Acoustic measures for vowels included duration, first (F1) and second (F2) formant frequency, and intensity ratio of F1/F2. For consonants, spectral moment coefficients and consonant-vowel (CV) boundary (intensity ratio between consonant and vowel) were measured. RESULTS: Face masks had a negative impact on speech intelligibility as measured by both intelligibility ratings. However, speech intelligibility was recovered in the clear speech condition for VAS but not for transcription scores. Analysis of orthographic transcription showed that listeners tended to frequently confuse consonants (particularly fricatives, affricates, and stops), rather than vowels in the word-initial position. Acoustic data indicated a significant effect of condition on CV intensity ratio only. CONCLUSIONS: Our data demonstrate a negative effect of face masks on speech intelligibility, mainly affecting consonants. However, intelligibility can be enhanced by speaking clearly, likely driven by prosodic alterations.

PTEN directs developmental and metabolic signaling for innate-like T cell fate and tissue homeostasis.

Phosphatase and tensin homologue (PTEN) is frequently mutated in human cancer, but its roles in lymphopoiesis and tissue homeostasis remain poorly defined. Here we show that PTEN orchestrates a two-step developmental process linking antigen receptor and IL-23-Stat3 signalling to type-17 innate-like T cell generation. Loss of PTEN leads to pronounced accumulation of mature IL-17-producing innate-like T cells in the thymus. IL-23 is essential for their accumulation, and ablation of IL-23 or IL-17 signalling rectifies the reduced survival of female PTEN-haploinsufficient mice that model human patients with PTEN mutations. Single-cell transcriptome and network analyses revealed the dynamic regulation of PTEN, mTOR and metabolic activities that accompanied type-17 cell programming. Furthermore, deletion of mTORC1 or mTORC2 blocks PTEN loss-driven type-17 cell accumulation, and this is further shaped by the Foxo1 and Stat3 pathways. Collectively, our study establishes developmental and metabolic signalling networks underpinning type-17 cell fate decisions and their functional effects at coordinating PTEN-dependent tissue homeostasis.

The Primary Process and Key Concepts of Economic Evaluation in Healthcare.

Economic evaluations in the healthcare are used to assess economic efficiency of pharmaceuticals and medical interventions such as diagnoses and medical procedures. This study introduces the main concepts of economic evaluation across its key steps: planning, outcome and cost calculation, modeling, cost-effectiveness results, uncertainty analysis, and decision-making. When planning an economic evaluation, we determine the study population, intervention, comparators, perspectives, time horizon, discount rates, and type of economic evaluation. In healthcare economic evaluations, outcomes include changes in mortality, the survival rate, life years, and quality-adjusted life years, while costs include medical, non-medical, and productivity costs. Model-based economic evaluations, including decision tree and Markov models, are mainly used to calculate the total costs and total effects. In cost-effectiveness or costutility analyses, cost-effectiveness is evaluated using the incremental cost-effectiveness ratio, which is the additional cost per one additional unit of effectiveness gained by an intervention compared with a comparator. All outcomes have uncertainties owing to limited evidence, diverse methodologies, and unexplained variation. Thus, researchers should review these uncertainties and confirm their robustness. We hope to contribute to the establishment and dissemination of economic evaluation methodologies that reflect Korean clinical and research environment and ultimately improve the rationality of healthcare policies.

The Reliability and Validity of Speech-Language Pathologists' Estimations of Intelligibility in Dysarthria.

This study examined the reliability and validity of speech-language pathologists' (SLP) estimations of speech intelligibility in dysarthria, including a visual analog scale (VAS) method and a percent estimation method commonly used in clinical settings. Speech samples from 20 speakers with dysarthria of varying etiologies were used to collect orthographic transcriptions from naïve listeners n=70 and VAS ratings and percent estimations of intelligibility from SLPs n=21. Intra- and interrater reliability for the two SLP intelligibility measures were evaluated, and the relationship between these measures was assessed. Finally, linear regression was used to evaluate the relationship between the naïve listeners' orthographic transcription scores and the two SLP intelligibility measures. The results indicated that the intrarater reliability for both SLP intelligibility measures was strong, and the interrater reliability between the SLP ratings was moderate to excellent. A moderate positive relationship between SLPs' VAS ratings and percent estimations was also observed. Finally, both SLPs' percent estimations and VAS ratings were predictive of naïve listeners' orthographic transcription scores, with SLPs' percent estimations being the strongest predictor. In conclusion, the average SLP percent estimations and VAS ratings are valid and reliable intelligibility measures. However, the validity and reliability of these measures vary between SLPs.

Health-Related Quality of Life of Patients with Cervical Cancer According to the Duration of Treatment and Cancer Progression.

OBJECTIVE: The purpose of this study was to assess health-related quality of life (HRQoL) in Korean patients with cervical cancer according to the duration of treatment and cancer progression of cervical cancer. METHODS: This study included 452 outpatients with cervical intraepithelial neoplasia (CIN) or invasive cervical cancer from six tertiary hospitals in South Korea. The questionnaire included the EQ-5D-3L instrument, patients' age, cancer progression (CIN or invasive cervical cancer), treatment duration (<1 year, ≥1 year but <2 years, and ≥2 years), treatment method (surgery, chemotherapy, radiation therapy), and presence of recurrence. HRQoL indices were calculated for these independent factors, and the mean was compared using ANOVA. Multiple regression analysis was performed to analyze factors affecting HRQoL in patients with cervical cancer. RESULTS: The EQ-5D index was 0.93 for patients with CIN, 0.87 for patients with invasive cervical cancer, and 0.78 for patients with recurrent invasive cervical cancer. HRQoL was significantly lower as the CIN progresses to cervical cancer. HRQoL of patients with invasive cervical cancer was lowest within 1 year of treatment in all stages. In addition, the HRQoL of patients with CIN or invasive cervical cancer who received chemotherapy and radiotherapy was lower than that of patients who underwent surgery. Multiple regression analysis showed that the HRQoL decreased significantly as increasing age, the first year of treatment after diagnosis, cancer recurrence, or chemotherapy. CONCLUSION: The HRQoL of patients with cervical cancer is affected not only by the stage of cancer progression but also by the duration of treatment and the type of treatment. As a result, when trying to apply the quality of life of patients with cervical cancer to cost-utility analysis, it is necessary to consider the duration and the type of treatment they receive.

Posttraumatic stress disorder and related factors among nurses working during the COVID-19 pandemic.

AIM: To analyse the prevalence of posttraumatic stress disorder (PTSD) and examine its related factors among nurses who worked during the coronavirus disease 2019 (COVID-19) pandemic in Daegu, South Korea. BACKGROUND: Nurses are a high-risk population for PTSD, especially during the COVID-19 pandemic. This study was conducted to identify the nursing work environmental factors that should be addressed to reduce PTSD. METHODS: Using a cross-sectional design, 365 nurses were enrolled. Their characteristics (intrapersonal, interpersonal, organizational, and COVID-19-related) and PTSD Checklist-5 scores were analysed. RESULTS: The average PTSD score was 14.98 ± 15.94, and 16.5% of the participants had a high risk of PTSD. Nurses were more likely to have PTSD if they were married (odds ratio = 3.02, p = .013) and when nurse managers' abilities, leadership, and support of nurses were low (odds ratio = 3.81, p < .001). CONCLUSIONS: The nursing work environment was found to be associated with PTSD. Therefore, interventions are necessary to increase nurse managers' abilities, leadership, and support for nurses to reduce the risk of PTSD among nurses. IMPLICATIONS FOR NURSING MANAGEMENT: Effective professional and social support and interventions to improve nurse managers' abilities, leadership, and support of nurses are needed to reduce PTSD.

Acoustic and Articulatory Characteristics of English Semivowels /ɹ, l, w/ Produced by Adult Second-Language Speakers.

PURPOSE: This study presents the results of acoustic and kinematic analyses of word-initial semivowels (/ɹ, l, w/) produced by second-language (L2) speakers of English whose native language is Korean. In addition, the relationship of acoustic and kinematic measures to the ratings of foreign accent was examined by correlation analyses. METHOD: Eleven L2 speakers and 10 native speakers (first language [L1]) of English read The Caterpillar passage. Acoustic and kinematic data were simultaneously recorded using an electromagnetic articulography system. In addition to speaking rate, two acoustic measures (ratio of third-formant [F3] frequency to second-formant [F2] frequency and duration of steady states of F2) and two kinematic measures (lip aperture and duration of lingual maximum hold) were obtained from individual target sounds. To examine the degree of contrast among the three sounds, acoustic and kinematic Euclidean distances were computed on the F2-F3 and x-y planes, respectively. RESULTS: Compared with L1 speakers, L2 speakers exhibited a significantly slower speaking rate. For the three semivowels, L2 speakers showed a reduced F3/F2 ratio during constriction, increased lip aperture, and reduced acoustic Euclidean distances among semivowels. Additionally, perceptual ratings of foreign accent were significantly correlated with three measures: duration of steady F2, acoustic Euclidean distance, and kinematic Euclidean distance. CONCLUSIONS: The findings provide acoustic and kinematic evidence for challenges that L2 speakers experience in the production of English semivowels, especially /ɹ/ and /w/. The robust and consistent finding of reduced contrasts among semivowels and their correlations with perceptual accent ratings suggests using sound contrasts as a potentially effective approach to accent modification paradigms.

Oral and Laryngeal Diadochokinesis Across the Life Span: A Scoping Review of Methods, Reference Data, and Clinical Applications.

PURPOSE: The aim of this study was to conduct a scoping review of research on oral and laryngeal diadochokinesis (DDK) in children and adults, either typically developing/developed or with a clinical diagnosis. METHOD: Searches were conducted with PubMed/MEDLINE, Google Scholar, CINAHL, and legacy sources in retrieved articles. Search terms included the following: DDK, alternating motion rate, maximum repetition rate, sequential motion rate, and syllable repetition rate. RESULTS: Three hundred sixty articles were retrieved and included in the review. Data source tables for children and adults list the number and ages of study participants, DDK task, and language(s) spoken. Cross-sectional data for typically developing children and typically developed adults are compiled for the monosyllables /pʌ/, /tʌ/, and /kʌ/; the trisyllable /pʌtʌkʌ/; and laryngeal DDK. In addition, DDK results are summarized for 26 disorders or conditions. DISCUSSION: A growing number of multidisciplinary reports on DDK affirm its role in clinical practice and research across the world. Atypical DDK is not a well-defined singular entity but rather a label for a collection of disturbances associated with diverse etiologies, including motoric, structural, sensory, and cognitive. The clinical value of DDK can be optimized by consideration of task parameters, analysis method, and population of interest.

Ovarian carcinoma immunoreactive antigen domain 2 controls mitochondrial apoptosis in lung adenocarcinoma.

Ovarian carcinoma immunoreactive antigen domain 2 (OCIAD2) has been reported to show significantly higher expression in invasive lung adenocarcinoma than in lung adenocarcinoma in situ, and its abnormal expression is associated with poorer prognosis of the patients. However, the cellular function of OCIAD2 in this tumor remains poorly understood. In the present study, we first validated that OCIAD2 showed higher expression in human lung adenocarcinoma tissues or cell lines than in normal lung tissue or immortalized normal bronchial epithelial cells. OCIAD2 was localized predominantly at the mitochondrial membrane in lung adenocarcinoma cells. Interestingly, suppression of OCIAD2 led to loss of mitochondrial structure and a reduction in the number of mitochondria. Moreover, OCIAD2 suppression led to downregulation of cellular growth, proliferation, migration, and invasion, and upregulation of mitochondria-related apoptosis. We also showed that OCIAD2 suppression induced a decrease in mitochondrial membrane potential and release of cytochrome c. Transcriptional profiling using RNA sequencing revealed a total of 137 genes whose expression was commonly altered after OCIAD2 knockdown in three lung adenocarcinoma cell lines (A549, HCC827, and PC9). Pathway enrichment analysis of those genes demonstrated significant enrichment in apoptotic signaling or endoplasmic reticulum (ER) stress pathways. Our data suggest that OCIAD2 inhibits the mitochondria-initiated apoptosis and thus promotes the survival of lung cancer cells. Therefore, OCIAD2 may be an effective target for treatment of lung adenocarcinoma.

Acoustic characteristics of Korean-English bilingual speakers' /l/ and the relationship to their foreign accent ratings.

PURPOSE: The current study examined acoustic characteristics of English /l/ produced by Korean speakers who speak English as their second language (KE). Comparisons were made to patterns of their Korean /l/ and English /l/ produced by monolingual speakers of American English (AE). Vowel context and word position effects on acoustic differences among the three /l/ sounds were examined in relation to the degree of foreign accentedness of KE speakers. METHODS: Korean and English word-initial and -final /l/ in two vowel contexts (high front vs. low back) were produced by 12 KE female adult speakers in a carrier phrase. A comparison group of 10 AE speakers produced English /l/. F1 and F2 values of each /l/ production were extracted at the /l/ midpoint and were compared to each other. Euclidean distances across the productions were also examined in relation to the degrees of foreign accentedness of KE speakers. RESULTS: KE speakers' English /l/ showed significantly lower F2-F1 values than their Korean /l/ across word position and vowel context but significantly higher F2-F1 values than AE speakers' English word-initial /l/. Euclidean distance between KE speakers' English and Korean /l/, and KE and AE speakers' English /l/ correlated significantly with KE speakers' degree of foreign accentedness across word position and vowel context. CONCLUSION: Results indicate that the influence of Korean on KE speakers' English /l/ productions varied by word position and vowel context, as well as the degree of their foreign accentedness ratings. This finding suggests the context-dependent nature of /l/ productions and highlights the need for considering a speakers' degree of foreign accent when exploring English /l/ patterns of KE speakers.

Feasibility study for simple on-line Raman spectroscopic detection of microplastic particles in water using perfluorocarbon as a particle-capturing medium.

A simple Raman spectroscopic scheme for on-line detection of microplastics (MPs) in water is demonstrated. Instead of using a conventional physical filter for MP separation, perfluorohexane (PFH, C6F14) was deployed as an MP-capturing medium in this study. When PFH was added into a water-filled L-shape tube, it formed a firm droplet at the bottom of the 90° curve due to its strong hydrophobicity and high density. When a tap water sample containing dispersed polyethylene (PE) particles was flowed through the L-tube, the contained PFH droplet effectively captured the PE particles, with an average recovery of 95.9%. Next, for reliable quantitative analysis, it was necessary to measure the entire PE particle captured PFH droplet in Raman spectral acquisition without partial spectroscopic sampling. Therefore, a wide area illumination (WAI) scheme providing a laser illumination diameter of 6 mm was adopted for sampling of the whole droplet. The intensity ratios of PE and PFH peaks in the collected spectra clearly increased with elevated quantities of dispersed PE particles. When samples of PE particles were measured in sea water, which possesses much higher ionic strength than does tap water, the shapes of PE particle-captured PFH droplets did not change, and the accuracy was maintained. Based on these results, the demonstrated analytical scheme is feasible for field analysis; further study is required to strengthen its utility.