Age Effects in L2 Perception and Production by Learners of Korean

This study examines perception and production by second language learners of Korean. The particular focus is word-initial aspirated and lax stops and affricates in Korean. The results of the learners with differing age of onset suggest the following: Early L2 exposure leads to better performance, which correlates strongly to the age of onset of L2 exposure. The perception and production of the early learners approximate that of the native speakers in this study. There was no interaction between segment types and their performance. On the other hand, the performance of the late learners exhibited characteristics different from that of the early learners. Their accuracy was lower than that of the early learners in perception and production of lax consonants. Segment type was a factor in their performance, which suggests L1 interference

An Alternative Model of Type A Dependence in a Gene Set of Correlated Genes

Klebanov et al. (2006) proposed a new type of stochastic dependence, Type A dependence, between gene expression levels. They estimated the abundance of Type A pairs by testing the correlation coefficients of gene pairs. We propose a new model, hidden regulator dependence, as an alternative to Type A dependence. We show that the correlation based procedure proposed by Klebanov et al. (2006) fails to differentiate hidden regulator dependence from Type A dependence, although their probabilistic structures are quite different.

The inhibitory effect of Gremlin-2 on adipogenesis suppresses breast cancer cell growth and metastasis

Abstract Background Gremlin-1 (GREM1) and Gremlin-2 (GREM2) are bone morphogenetic protein antagonists that play important roles in organogenesis, tissue differentiation, and tissue homeostasis. Although GREM1 has been reported to be involved in promoting various cancers, little has been reported about effects of GREM2 on cancer. Recently, it has been reported that GREM2 can inhibit adipogenesis in adipose-derived stromal/stem cells. However, as an inhibitor of adipogenesis, the role of GREM2 in cancer progression is not well understood yet. Methods Pre-adipocyte 3T3-L1 cells overexpressing mock or Grem2 were established using a lentiviral transduction system and differentiated into adipocytes-mock and adipocytes-Grem2, respectively. To investigate the effect of adipocyte-Grem2 on breast cancer cells, we analyzed the proliferative and invasion abilities of spheroids using a 3D co-culture system of breast cancer cells and adipocytes or conditioned medium (CM) of adipocytes. An orthotopic breast cancer mouse model was used to examine the role of adipocytes-Grem2 in breast cancer progression. Results Grem2 overexpression suppressed adipogenesis of 3T3-L1 cells. Proliferative and invasion abilities of spheroids formed by co-culturing MTV/TM-011 breast cancer cells and adipocytes-Grem2 were significantly reduced compared to those of spheroids formed by co-culturing MTV/TM-011 cells and adipocytes-mock. Compared to adipocytes-mock, adipocytes-Grem2 showed decreased mRNA expression of several adipokines, notably IL-6. The concentration of IL-6 in the CM of these cells was also decreased. Proliferative and invasive abilities of breast cancer cells reduced by adipocytes-Grem2 were restored by IL-6 treatment. Expression levels of vimentin, slug, and twist1 in breast cancer cells were decreased by treatment with CM of adipocytes-Grem2 but increased by IL-6 treatment. In orthotopic breast cancer mouse model, mice injected with both MTV/TM-011 cells and adipocytes-Grem2 showed smaller primary tumors and lower lung metastasis than controls. However, IL-6 administration increased both the size of primary tumor and the number of metastatic lung lesions, which were reduced by adipocytes-Grem2. Conclusions Our study suggests that GREM2 overexpression in adipocytes can inhibit adipogenesis, reduce the expression and secretion of several adipokines, including IL-6, and ultimately inhibit breast cancer progression

Advanced Maternal Age Deteriorates the Developmental Competence of Vitrified Oocytes in Mice

Advanced maternal age (AMA) is known to be related to the decrease in the quality and quantity of oocytes. Oocyte vitrification is now considered an established assisted reproductive technology for fertility preservation. However, it remains unclear whether the oocytes in older women are more sensitive to various insults during vitrification. Thus, we evaluated whether AMA affects cellular and molecular features and developmental outcomes of oocytes after vitrification in mice. The oocytes were grouped as young fresh (YF), young vitrified/warmed (YV), aged fresh (AF), and aged vitrified/warmed (AV). The survival rate of AV oocytes was significantly lower than that of YV oocytes. The rates of fertilization, cleavage, and blastocyst formation of AV oocytes were significantly lower than those of other groups. AV oocytes were represented as aberrations in mitochondria distribution, microvacuole size, and autophagosome formation, leading to delayed embryo development in mice. This delay was associated with a reduced number of total cells and trophectoderm in the blastocyst developed from AV oocytes. Collectively, AMA exaggerates the vulnerability of oocytes to cryo-damage that occurs during vitrification in mice, suggesting that the current vitrification protocols optimized for oocytes from young females should be modified for oocytes from aged women

Molecularly engineered linear organic carbonates as practically viable nonflammable electrolytes for safe Li-ion batteries

<jats:p>Concurrent modification of linear carbonates combining alkyl-chain extension and alkoxy substitution enables thermally stable high-performance batteries by decreasing volatility and increasing solvation ability simultaneously.</jats:p&gt