525 research outputs found

    Heritage Language Development and Maintenance of Heritage Speakers of Korean in Australia in Primary School Years

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    Sparked by the interesting observation of non-native acquisition of heritage languages despite early and continuous exposure, the study of heritage languages has endeavoured to explore the end results of heritage language acquisition while mostly neglecting the pathway that heritage speakers undergo before arriving in that state. This study investigated how the heritage language develops and is maintained over primary school years in heritage speakers of Korean who grow up in Australia. Linguistic abilities in Korean of 243 heritage speakers of Korean of primary school age in Australia, compared to their school-year-level-matched native speakers of Korean in the Republic of Korean (South Korea), have been examined in the three broad linguistic areas of the sound system, lexis and grammar with a battery of tasks. The results of the tasks indicated that the heritage speakers generally fell behind the native speakers in the linguistic abilities in Korean examined but their gap to the native speaker controls differed between the linguistic areas examined. Regarding the sound system, the heritage speakers did not show reliably lower perception of speech sounds in Korean than those of the native speakers, and their speech sound perception, which is supposed to have developed and been stabilised in early childhood, appeared to be retained well over primary school years. On the contrary, they exhibited a great shortfall in lexical knowledge in Korean compared to their native speaker peers, and this gap appeared to widen from the middle primary school year levels where the lexical knowledge of the native speakers expands explosively. In comparison, their linguistic abilities in grammar exhibited a varying degree of divergence to the native speaker norms by linguistic aspect. The results suggested that they acquired basic syntactic structures and semantic features that develop early in first language acquisition of Korean to a level comparable to that of their native speaker peers and their understanding of sentences made of such linguistic aspects was maintained well over the primary school period. In contrast, they exhibited a considerable delay in the acquisition of certain grammatical aspects that are mastered relatively late by the native speakers, and the heritage speakers’ acquisition of these aspects did not seem to progress greatly over primary school years. They also showed a substantial gap to the native speaker controls in understanding passive sentences and scrambled active sentences, and this gap is likely to have arisen from their greater processing difficulty. Mostly paralleling the linguistic abilities of adult heritage speakers attested in previous research, the results of this study underline that the linguistic abilities in Korean of heritage speakers of Korean in Australia diverge from their (age- or) school-year-level-appropriate native norms already in their primary school years. Although the linguistic aspects that are mastered early in first language acquisition such as phoneme distinction or basic syntactic structures seem to be acquired to a level comparable to their school-year-level-appropriate native norms and be retained well over the first half of their compulsory schooling, the linguistic abilities that should develop further through primary school years show signs of stagnation (if not attrition) and such signs are much more prominent at the middle primary school year levels. This implies that in Australia where EnglishKorean bilingual education programs are not readily accessible to heritage speakers of Korean, it will be extremely difficult for them to develop high proficiency in Korean which requires mastery of complex grammatical aspects and extensive vocabulary. The results of this study not only alarm the Korean ethnolinguistic community in Australia and other stakeholders about the level of Korean language abilities developed and maintained by the heritage speakers in primary school years, but also provide detailed information on in which linguistic aspects they may have greater delays in the development, by which degree they show such delays and when the delays are likely to intensify over the course of primary school years

    Late-time Phase transition and the Galactic halo as a Bose Liquid: (II) the Effect of Visible Matter

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    In the previous work, we investigated the rotation curves of galaxies assuming that the dark matter consists of ultra light boson appearing in ′'late time phase transition' theory. Generalizing this work, we consider the effect of visible matter and classify the types of rotation curves as we vary the fraction of the mass and extention of visible matter. We show that visible matter, in galaxies with flat rotation curves, has mass fraction 2%∼10% 2\% \sim 10\% and it is confined within the distance fraction 10%∼20% 10\% \sim 20\%.Comment: 10 pages, 10 figures included, to appear in Phys. Rev. D50,p365

    Improvement of retinoids production in recombinant E. coli using glyoxylic acid

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    Isoprenoids are the most chemically diverse compounds found in nature. They are present in all organisms and have essential roles in membrane structure, redox chemistry, reproductive cycles, growth regulation, signal transduction and defense mechanisms. In spite of their diversity of functions and structures, all isoprenoids are derived from the common building blocks of isopentenyl diphosphate (IPP) and its isomer dimethylallyl diphosphate (DMAPP). Optimization of IPP synthesis pathway is of benefit to mass production of various isoprenoids. There are two pathways of 2-C-Methyl-D-erythritol-4-phosphate (MEP) and mevalonate (MVA) for IPP synthesis. Prokaryotes including E. coli generally use MEP pathway whereas MVA pathway is used in eukaryotes. To improve isoprenoid production, it was performed the deletion of genes in E. coli, which are involved in both formation of fermentation by-products such as organic acids and alcohols, and consumption of precursors of MEP and MVA pathways, pyruvate and acetyl-CoA. As a result, we were able to develop a strain with improved fermentation productivity and carbon source utilization efficiency, the mutant strain was called AceCo. Higher lycopene production was achieved in the AceCo strain compared to the wild type MG1655 strain due to no formation of the inhibitory by-products. However, retinoids production of AceCo strain decreased to a half of that of MG1655 strain. Please click Additional Files below to see the full abstract

    Enhanced Chromatin Accessibility and Recruitment of JUNB Mediate the Sustained IL-4 Expression in NFAT1 Deficient T Helper 2 Cells

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    Nuclear factor of activated T cells (NFAT) is a family of transcription factors composed of five proteins. Among them, NFAT1 is a predominant NFAT protein in CD4+ T cells. NFAT1 positively regulates transcription of a large number of inducible cytokine genes including IL-2, IL-4, IL-5 and other cytokines. However, disruption of NFAT1 results in an unexpected increase of IL-4. In this study, we have investigated the role of NFAT1 in regulation of IL-4 gene expression in T helper 2 cells (Th2) from an epigenetic viewpoint. NFAT1 deficient Th2 cells showed a sustained IL-4 expression while wild type (WT) cells reduced its expression. We tested whether epigenetic maintenance and changes in the chromatin architecture of IL-4 promoter locus play a role in differential IL-4 transcription between in WT and NFAT1 deficient Th2 cells. Compared with WT, NFAT1 deficient CD4+ Th2 cells exhibited enhanced chromatin accessibility with permissive histone modification and DNA demethylation in the IL-4 promoter region. Transcription factors bound to IL-4 promoter region in the absence of NFAT1 were identified by Micro-LC/LC-MS/MS analysis. Among the candidates, preferential recruitment of JUNB to the IL-4 promoter was confirmed by chromatin immunoprecipitation analysis. Overexpression of JUNB together with SATB1 synergistically upregulated IL-4 promoter activity, while knockdown JUNB significantly reduced IL-4 expression. Our results suggest that the prolonged IL-4 expression in NFAT1 deficient Th2 cells is mediated by preferential binding of JUNB/SATB1 to the IL-4 promoter with permissive chromatin architecture

    Prevalence of sarcopenia and sarcopenic obesity in Korean adults: The Korean Sarcopenic Obesity Study (KSOS)

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    *Context:* Sarcopenic obesity (SO), a combination of excess weight and reduced muscle mass and/or strength, is suggested to be associated with an increased risk of adverse health outcomes. 
*Objectives:* To examine the prevalence and characteristics of Sarcopenic and SO defined by using different indices such as Appendicular Skeletal muscle Mass (ASM)/height^2^ and Skeletal Muscle Index (SMI (%): skeletal muscle mass (kg)/weight (kg) × 100) for Korean adults. 
*Methods:* 591 participants were recruited from the Korean Sarcopenic Obesity Study (KSOS) which is an ongoing prospective observational cohort study. Analysis was conducted in 526 participants (328 women, 198 men) who had complete data on body composition using Dual X-ray absorptiometry and computed tomography. 
*Results:* The prevalence of sarcopenia and SO increases with aging. Using two or more standard deviations (SD) of ASM/height^2^ below reference values from young, healthy adults as a definition of sarcopenia, the prevalence of sarcopenia and SO was 6.3% and 1.3% in men and 4.1% and 1.7% in women over 60 years of age. However, using two or more SD of SMI, the prevalence of sarcopenia and SO was 5.1% and 5.1% respectively in men and 14.2% and 12.5% respectively in women. As defined by SMI, subjects with SO had 3 times the risk of metabolic syndrome (OR = 3.03, 95% confidence interval (CI) = 1.26-7.26) and subjects with non-sarcopenic obesity had approximately 2 times the risk of metabolic syndrome (OR = 1.89, 95% CI = 1.18-3.02) compared with normal subjects. 
*Conclusion:* Obese subjects with relative sarcopenia were associated with a greater likelihood for metabolic syndrome. As Koreans were more obese and aging, the prevalence of SO and its impact on health outcomes are estimated to be rapidly grow. Further research is requested to establish the definition, cause and consequences of SO.
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    Comparison of on-Statin Lipid and Lipoprotein Levels for the Prediction of First Cardiovascular Event in Type 2 Diabetes Mellitus

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    Background A substantial cardiovascular disease risk remains even after optimal statin therapy. Comparative predictiveness of major lipid and lipoprotein parameters for cardiovascular events in patients with type 2 diabetes mellitus (T2DM) who are treated with statins is not well documented. Methods From the Korean Nationwide Cohort, 11,900 patients with T2DM (≥40 years of age) without a history of cardiovascular disease and receiving moderate- or high-intensity statins were included. The primary outcome was the first occurrence of major adverse cardiovascular events (MACE) including ischemic heart disease, ischemic stroke, and cardiovascular death. The risk of MACE was estimated according to on-statin levels of low-density lipoprotein cholesterol (LDL-C), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and non-HDL-C. Results MACE occurred in 712 patients during a median follow-up period of 37.9 months (interquartile range, 21.7 to 54.9). Among patients achieving LDL-C levels less than 100 mg/dL, the hazard ratios for MACE per 1-standard deviation change in on-treatment values were 1.25 (95% confidence interval [CI], 1.07 to 1.47) for LDL-C, 1.31 (95% CI, 1.09 to 1.57) for non-HDL-C, 1.05 (95% CI, 0.91 to 1.21) for TG, and 1.16 (95% CI, 0.98 to 1.37) for HDL-C, after adjusting for potential confounders and lipid parameters mutually. The predictive ability of on-statin LDL-C and non-HDL-C for MACE was prominent in patients at high cardiovascular risk or those with LDL-C ≥70 mg/dL. Conclusion On-statin LDL-C and non-HDL-C levels are better predictors of the first cardiovascular event than TG or HDL-C in patients with T2DM

    Acral-type Malignant Acanthosis Nigricans Associated with Gastric Adenocarcinoma

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    Acanthosis nigricans is a symmetric eruption characterized by the presence of a hyperpigmented, velvety cutaneous thickening, that can develop on any part of the body, but characteristically affects the flexural areas of the body. The velvety hyperkeratotic lesions can be located on the dorsum of the hands and feet in dark-skinned people in the form of a variant of acanthosis nigricans called as acral acanthotic anomaly or acral type acanthosis nigricans. Although acanthosis nigricans is associated with malignant tumors, particularly gastric carcinoma, acral type acanthosis nigricans has never been reported to be associated with gastric adenocarcinoma. In our present study, we describe a case of 58-year-old man with acral type acanthosis nigricans and its association with carcinoma of the stomach; a marked improvement was seen in the skin condition of the patient with chemotherapy
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