Korean Child-Rearing Practices in the United States: An Ethnographic Study on Korean Immigrants in the Cultural Transition

Digitized thesi

THE MECHANISM OF RNA INTERFERENCE IN ARTHROPODS

RNA interference (RNAi) is a useful reverse genetics tool for investigation of gene function as well as for practical applications in many fields including medicine and agriculture. Due to the variability in RNAi efficiency, RNAi-based methods are currently being developed for controlling only coleopteran insects which are known to be amenable to RNAi. The first chapter of my thesis includes findings from research to investigate what are the factors that make coleopteran insects relatively more efficient in RNAi. I used Colorado potato beetle (CPB), Leptinotarsa decemlineata and its cell line (Lepd-SL1) as study models to identify genes that play key roles in RNAi pathway. Five genes including Argonaute-1 (microRNA Argonaute) and Aubergine (PiwiRNA Argonaute) were identified as those required for siRNA (short interfering RNA) RNAi pathway. I also found that RNAi is completely blocked in StaufenC knockdown cells. StaufenC belongs to dsRNA binding protein family and binds to dsRNA as shown by gel mobility shift and the pull-down assays. Interestingly, I also found that StaufenC is downregulated in RNAi resistant cells and StaufenC homologous sequences are present in only coleopteran insects where RNAi works efficiently. These data suggest that StaufenC is a major contributor to efficient RNAi in coleopteran insects and is a potential target for RNAi resistance. The second part of my research is to understand the mechanisms of RNAi in those insects refractory to RNAi. The barriers for successful RNAi include the presence of double-stranded ribonucleases (dsRNase) in the lumen and hemolymph that could potentially digest double-stranded RNA (dsRNA) and the variability in the transport of dsRNA into and within the cells. Recent work in our laboratory showed that the dsRNAs are transported into lepidopteran cells, but they are not processed into siRNAs because they are trapped in acidic bodies. I focused on identification of these acidic bodies in which dsRNAs accumulate in Spodoptera frugiperda Sf9 cells. These studies showed that entrapment of internalized dsRNA in endosomes is one of the major factors contributing to inefficient RNAi. Overall, my research revealed important players involved in successful and unsuccessful RNAi in insects

Electric Field Enhanced Hydrogen Storage on BN Sheet

Using density functional theory we show that an applied electric field substantially improves the hydrogen storage properties of a BN sheet by polarizing the hydrogen molecules as well as the substrate. The adsorption energy of a single H2 molecule in the presence of an electric field of 0.05 a.u. is 0.48 eV compared to 0.07 eV in its absence. When one layer of H2 molecules is adsorbed, the binding energy per H2 molecule increases from 0.03 eV in the field-free case to 0.14 eV/H2 in the presence of an electric field of 0.045 a.u. The corresponding gravimetric density of 7.5 wt % is consistent with the 6 wt % system target set by DOE for 2010. Once the applied electric field is removed, the stored H2 molecules can be easily released, thus making the storage reversible.Comment: submitted to Phys. Rev. Lett. 15 pages with 6 figure

La continuación de Nicolás Núñez a Cárcel de amor.

Sin resume

Probiotics, Nuclear Receptor Signaling, and Anti-Inflammatory Pathways

There is increased investigation of the human microbiome as it relates to health and disease. Dysbiosis is implicated in various clinical conditions including inflammatory bowel disease (IBD). Probiotics have been explored as a potential treatment for IBD and other diseases. The mechanism of action for probiotics has yet to be fully elucidated. This paper discusses novel mechanisms of action for probiotics involving anti-inflammatory signaling pathways. We highlight recent progress in probiotics and nuclear receptor signaling, such as peroxisome-proliferator-activated receptor gamma (PPARγ) and vitamin D receptor (VDR). We also discuss future areas of investigation

TT‾T\overline{T} Deformation of N=(1,1)\mathcal{N}=(1,1) Off-Shell Supersymmetry and Partially Broken Supersymmetry

We construct the superaction for the $T\overline{T}$ deformation of 2D free $\mathcal{N}=(1,1)$ supersymmetric model with a deformed superfield. We show that the $\mathcal{N}=(1,1)$ off-shell is deformed under the $T\overline{T}$ deformation, which is reflected by the deformed superfield. We interpret this superaction as an effective action of the Goldstone superfield for the partial spontaneous breaking of $\mathcal{N}=(2,2)$ supersymmetry to $\mathcal{N}=(1,1)$. We demonstrate that the unbroken and broken supersymmetry of the effective superaction corresponds to the off-shell $\mathcal{N}=(1,1)$ supersymmetry and the off-shell fermi global non-linear symmetry in the $T\overline{T}$-deformed theory, respectively. We show that this effective superaction can be obtained by the non-linear realization of the partially broken global supersymmetry (PBGS) from the coset superspace. Furthermore, we reproduce the superaction by the constrained superfield method accompanied by a field redefinition.Comment: 33 pages; v2: reference adde