Doctor of Philosophy

dissertationIt has been acknowledged in the research on bilingualism that bilingual speakers, regardless of age, exhibit enhanced cognitive control capacity (e.g., interference control) as compared with their monolingual peers. Behavior and imaging studies suggest that these effects are the result of a shared neural network recruited by both linguistic processing and general-purpose cognitive control in bilinguals. The majority of studies on bilingual cognitive control examine two groupsâ€"an early bilingual group (individuals who have been exposed to two languages from a very early age) vs. a monolingual control group. Late bilinguals (i.e., people who acquire a second language later in life) are often excluded in studies of bilingual cognitive control. Yet it is precisely this population that makes up the majority of bilinguals in United States. This dissertation study compares an early bilingual group with two late bilingual groups in order to examine whether the cognitive processing advantage observed in bilinguals was associated with age of acquisition (AOA) or language proficiency. Data on cognitive control capacity were collected through three lab tasks that measured working memory capacity (WMC), response inhibition, and interference control, respectively. Results found that successful inhibition of prepotent responses was associated with higher WMC, later AOA, and higher language proficiency, while successful interference suppression was associated with higher WMC, earlier AOA, and higher language proficiency. An efficient speed-accuracy trade-off pattern was also observed in early bilinguals. Findings from this study are discussed under the framework of the adaptive control hypothesis

Doctor of Philosophy

dissertationIt has been acknowledged in the research on bilingualism that bilingual speakers, regardless of age, exhibit enhanced cognitive control capacity (e.g., interference control) as compared with their monolingual peers. Behavior and imaging studies suggest that these effects are the result of a shared neural network recruited by both linguistic processing and general-purpose cognitive control in bilinguals. The majority of studies on bilingual cognitive control examine two groups—an early bilingual group (individuals who have been exposed to two languages from a very early age) vs. a monolingual control group. Late bilinguals (i.e., people who acquire a second language later in life) are often excluded in studies of bilingual cognitive control. Yet it is precisely this population that makes up the majority of bilinguals in United States. This dissertation study compares an early bilingual group with two late bilingual groups in order to examine whether the cognitive processing advantage observed in bilinguals was associated with age of acquisition (AOA) or language proficiency. Data on cognitive control capacity were collected through three lab tasks that measured working memory capacity (WMC), response inhibition, and interference control, respectively. Results found that successful inhibition of prepotent responses was associated with higher WMC, later AOA, and higher language proficiency, while successful interference suppression was associated with higher WMC, earlier AOA, and higher language proficiency. An efficient speed-accuracy trade-off pattern was also observed in early bilinguals. Findings from this study are discussed under the framework of the adaptive control hypothesis

VIGAN: Missing View Imputation with Generative Adversarial Networks

In an era when big data are becoming the norm, there is less concern with the quantity but more with the quality and completeness of the data. In many disciplines, data are collected from heterogeneous sources, resulting in multi-view or multi-modal datasets. The missing data problem has been challenging to address in multi-view data analysis. Especially, when certain samples miss an entire view of data, it creates the missing view problem. Classic multiple imputations or matrix completion methods are hardly effective here when no information can be based on in the specific view to impute data for such samples. The commonly-used simple method of removing samples with a missing view can dramatically reduce sample size, thus diminishing the statistical power of a subsequent analysis. In this paper, we propose a novel approach for view imputation via generative adversarial networks (GANs), which we name by VIGAN. This approach first treats each view as a separate domain and identifies domain-to-domain mappings via a GAN using randomly-sampled data from each view, and then employs a multi-modal denoising autoencoder (DAE) to reconstruct the missing view from the GAN outputs based on paired data across the views. Then, by optimizing the GAN and DAE jointly, our model enables the knowledge integration for domain mappings and view correspondences to effectively recover the missing view. Empirical results on benchmark datasets validate the VIGAN approach by comparing against the state of the art. The evaluation of VIGAN in a genetic study of substance use disorders further proves the effectiveness and usability of this approach in life science.Comment: 10 pages, 8 figures, conferenc

Silencing of two insulin receptor genes disrupts nymph-adult transition of alate brown citrus aphid

Insulin receptors play key roles in growth, development, and polymorphism in insects. Here, we report two insulin receptor genes (AcInR1 and AcInR2) from the brown citrus aphid, Aphis (Toxoptera) citricidus. Transcriptional analyses showed that AcInR1 increased during the nymph-adult transition in alate aphids, while AcInR2 had the highest expression level in second instar nymphs. AcInR1 is important in aphid development from fourth instar nymphs to adults as verified by dsRNA feeding mediated RNAi. The silencing of AcInR1 or/and AcInR2 produced a variety of phenotypes including adults with normal wings, malformed wings, under-developed wings, and aphids failing to develop beyond the nymphal stages. Silencing of AcInR1 or AcInR2 alone, and co-silencing of both genes, resulted in 73% or 60%, and 87% of aphids with problems in the transition from nymph to normal adult. The co-silencing of AcInR1 and AcInR2 resulted in 62% dead nymphs, but no mortality occurred by silencing of AcInR1 or AcInR2 alone. Phenotypes of adults in the dsInR1 and dsInR2 were similar. The results demonstrate that AcInR1 and AcInR2 are essential for successful nymph-adult transition in alate aphids and show that RNAi methods may be useful for the management of this pest

An Effective On-line Polymer Characterization Technique by Using SALS Image Processing Software and Wavelet Analysis

This paper describes an effective on-line polymer characterization technique by using small-angle light-scattering (SALS) image processing software and wavelet analysis. The phenomenon of small-angle light scattering has been applied to give information about transparent structures on morphology. Real-time visualization of various scattered light image and light intensity matrices is performed by the optical image real-time processing software for SALS. The software can measure the signal intensity of light scattering images, draw the frequency-intensity curves and the amplitude-intensity curves to indicate the variation of the intensity of scattered light in different processing conditions, and estimate the parameters. The current study utilizes a one-dimensional wavelet to delete noise from the original SALS signal and estimate the variation trend of maximum intensity area of the scattered light. So, the system brought the qualitative analysis of the structural information of transparent film success

Effects of flavonoids derived from Taxus yunnanensis on p-glycoprotein and cytochrome P450 3A4

AbstractThe intestinal uptake of paclitaxel is hampered by trans-membrane efflux transporters such as P-glycoprotein (P-gp), and paclitaxel is mainly metabolized by cytochrome P450 3A4 (CYP3A4) presented in the liver. Our previous results demonstrated that flavonoids extracted from Taxus yunnanensis could improve the oral absorption of paclitaxel. The current study was purposed to investigate the effects of the flavonoid extracts on P-gp and CYP3A4 in vitro. The expression and activity of P-gp were detected by western blotting and intracellular rhodamine 123 accumulation assay in Caco-2 cells treated with the flavonoids extract. The expression of CYP3A4 was investigated by western blotting in mouse primary hepatocytes and the activity of CYP3A4 was detected by LC-MS/MS method using rat liver microsomes. Our results showed that the flavonoid extracts from T. yunnanensis could inhibit P-gp activity and concurrently decrease the expression and activity of CYP3A4. In conclusion, activity of P-gp and CYP3A4 could be inhibited by flavonoids extracted from T. yunnanensis which might be potential candidates for development of oral formulation of paclitaxel