The fruit of Cornus officinalis Sieb. et Zucc. is commonly prescribed in Asian countries as a tonic formula. In this study, the hepatoprotective effect of ethanolic extracts of the fruit of C. officinalis (ECO) was investigated in a mouse model of acetaminophen- (APAP-) induced liver injury. Pretreatment of mice with ECO (100, 250, and 500 mg/kg for 7 days) significantly prevented the APAP (200 mg/kg) induced hepatic damage as indicated by the serum marker enzymes (AST, ALT, and LDH). Parallel to these changes, ECO treatment also prevented APAP-induced oxidative stress in the mice liver by inhibiting lipid peroxidation (MDA) and restoring the levels of antioxidant enzymes (SOD, CAT, and HO-1) and glutathione. Liver injury and collagen accumulation were assessed using histological studies by hematoxylin and eosin staining. Our results indicate that ECO can prevent hepatic injuries associated with APAP-induced hepatotoxicity by preventing or alleviating oxidative stress.
BACKGROUND: Organic–inorganic nanocomposites were prepared by copolymerization of various monomers and polyhedral oligomeric silsesquioxane (POSS) derivatives. Preliminary results showed that styrene/styryl–POSS copolymers could be obtained using CpTiCl3 catalyst. In the work reported here, the copolymerization of styrene and styryl‐substituted POSS was studied in detail for a more effective catalyst, Cp*TiCl3. RESULTS: The glass transition temperature (Tg) of the copolymers prepared increased with increasing POSS content. The degradation temperature (Td) of the copolymers was 60 °C higher than that of syndiotactic polystyrene under nitrogen. Although the thermal properties were improved by incorporation of POSS, the catalytic activity decreased with POSS content. The racemic triad and syndiotactic index of the copolymers decreased with increasing POSS content. Gel permeation chromatograms of the copolymers exhibited multimodal distribution due to the presence of multi‐active centres, which were formed by interaction of Ti with the POSS siloxane linkage. CONCLUSION: With the incorporation of POSS, the thermal properties of polystyrene were improved. The styrene/styryl–POSS copolymers are formed through the various active sites arising from the interactions of Ti with POSS. Copyright © 2008 Society of Chemical Industry
This study acoustically examines the quality of fricatives produced by ten dysarthric speakers with cerebral palsy. Previous similar studies tend to focus only on sibilants, but to obtain a better understanding of how dysarthria affects fricatives we selected a range of samples with different places of articulation and voicing. The Universal Access (UA) Speech database was used to select thirteen words beginning with one of the English fricatives (
Previous research has suggested that the production of speech rhythm in a second language (L2) or foreign language is influenced by the speaker’s first language rhythm. However, it is less clear how the production of L2 rhythm is affected by the learners’ L2 proficiency, largely due to the lack of rhythm metrics that show consistent results between studies. We examined the production of English rhythm by 75 Korean learners with the rhythm metrics proposed in previous studies (pairwise variability indices and interval measures). We also devised new sentence stress measures (i.e., accentuation rate and accentuation error rate) and investigated whether these new measures can quantify rhythmic differences between the learners. The results found no rhythm metric that significantly correlated with proficiency in the expected direction. In contrast, we found a significant correlation between the learners’ proficiency levels and both measures of sentence stress, showing that less-proficient learners placed sentence stress on more words and made more sentence stress errors. This demonstrates that our measures of sentence stress can be used as effective features for assessing Korean learners’ English rhythm proficiency.
This paper aims to propose a gradient of learnability as a criterion for setting priorities in pronunciation teaching. A total of 40 Korean subjects (mostly aged 12 year) were tested on their discrimination ability of English sounds before and after participating in a high variability phonetic training (HVPT) program for 4 weeks. This study shows highly promising results for pronunciation teaching with the HVPT method. First, lower level learners show greater improvements in phoneme discrimination ability compared to upper level learners. Second, consonants are better discriminated than vowels and greater improvements are seen with consonant contrasts than with vowels that have a lower functional load. Third, many of the sounds with high functional load have a high learnability. Fourth, greater improvements are seen with sounds that are poorly identified before the training than sounds that are well-identified. Fifth, young learners also benefit from the HVPT, much like highly motivated adult learners. A learnability gradient was established on the basis of the phoneme learnability index and the pairwise learnability index. On the basis of the constructed gradient of learnability and the concept of functional load, a set of priorities was provided for teaching English pronunciation to young Korean learners.
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