Although many learners are able to learn vast amounts of vocabulary and master the grammar of another language, many learners find difficulty in mastering the sounds of another language. Korean, in particular has a set of consonants that seem strikingly similar to English speakers, which makes it arduous to tell them apart. For example, the words for 'moon' and 'mask' in Korean, pronounced [tal], both begin with a [t] but are produced slightly differently with the [t] in 'moon' unaspirated and the [t] in 'mask' aspirated (Aspiration refers to the puff of air that can accompany certain sounds like [b, p, t, d, k, g]). Research has shown the pitch of the vowel following these consonants can also serve as a reliable cue, with the vowels following aspirated sounds having a higher pitch than the vowels following the unaspirated sounds.

In this study, I examined whether training learners of Korean to recognize this cue can help them better discriminate between these consonants. In order to test this, learners were asked to take a short survey where they watched a video that explains these cues. They then were tested on their perception of these consonants by taking a matching quiz where they were asked to listen to a set of audio files to gauge any possible improvements. With this training, it was expected that learners of Korean could better segregate these consonants with better accuracy. It is hoped that this study will bring attention to the need to improve pronunciation education and pave the way towards further research in teaching learners of Korean not only how to better perceive these sounds, but also pronounce these sounds as well.
 

 Glioblastoma multiforme (GBM) is the most common and deadliest cancer of the central nervous system. The existence of stem-like cells within GBM tumors - Glioblastoma stem cells (GSCs) - may explain some of the malignant features of Glioblastoma multiforme (GBM) owing to their rapid self renewal and diffuse migratory behavior. Increasingly apparent is the role ion channels play in many cancer cell properties, including regulation of cell cycle progression and proliferation, tumor cell motility and invasion, and regulation of metabolic rate. We hypothesize that ion channel dysregulation contributes to GSC malignancy, including increased viability, proliferation, and migration. To test this, multiple GSC isolates derived from human GBM tumors were maintained in culture over many passages while retaining stem cell properties. RNA-seq expression profiles revealed ion channel families that were highly enriched in GSC samples. Real-time qPCR was next used to confirm increased expression of voltage gated calcium, sodium, and potassium channels, ionotropic glutamate channels and inwardly-rectifying potassium channels. Identifying ion channels uniquely enriched in GSCs led to functional analyses to determine how ion channel blockers affected their proliferative and migratory properties. We performed MTT cell viability assays to assess how ion channel blockers altered the viability of GSCs compared to a control neural stem cell line. We were able to show a significant decrease in cell viability across GSC lines compared to control at a variety of drug concentrations. Utilizing live-image cell tracking, we determined decreased migratory behavior and rates of these GSC lines with the same blockers. Finally, to elucidate the role of the extrinsic tumour microenvironment on the proliferation and migration of GSCs, unique coculture models involving GSCs cultured on mouse organotypic brain slices were utilized, and showed the affects of stimulating and inhibitory DREADD receptors to modulate local neuronal activity.

Intestine is responsible for the biotransformation of many orally-exposed chemicals. The nuclear receptor constitutive androstane receptor (CAR/Nr1i3) can be activated by various drugs and environmental chemicals, and in turn it is known to up-regulate the expression of many drug-processing genes (DPGs) in liver to facilitate xenobiotic biotransformation. However, relatively less is known regarding the effect of CAR on the basal and inducible expression of DPGs in various sections of intestine. To fill this critical knowledge gap, sixty-day-old wild-type and CAR-null mice were administered the CAR-ligand TCPOBOP (3mg/kg, i.p.) or vehicle once daily for 4-days. CAR-null mice had altered basal expression of many DPGs in a section-specific manner in intestine. Consistent with the liver data (Aleksunes and Klaassen, 2012), TCPOBOP up-regulated many DPGs in specific sections of small intestine in a CAR-dependent manner. In contrast, the mRNAs of certain DPGs were previously known to be up-regulated by TCPOBOP in liver but were not altered in intestine. Interestingly, many known CAR-target genes were highest expressed in colon where CAR is minimally expressed, suggesting that additional regulators are involved in regulating their expression. In conclusion, the present study has shown that CAR is critical in both maintaining the basal expression as well as the pharmacological regulation of certain DPGs in a section-specific manner of the intestine, and the CAR activation in liver and intestine produces overlapping but not identical results. Therefore, Identification of the xenobiotic responses to CAR activation in intestine is critical for further understanding the adverse drug-drug interactions for many orally-exposed chemicals.

The South Pacific Convergence Zone (SPCZ) is the most prominent rain feature of the Southern Hemisphere, but is a very understudied region. Changes in the SPCZ can affect freshwater availability to people living on the islands in the South Pacific. The satellite record shows precipitation patterns from the past 37 years; in the tropics the best way to investigate rainfall before 1979 is to examine lake sediment. We used sediment cores with age models from Barora Lake, a shallow freshwater lake in the Solomon Islands, to obtain a detailed view of past rainfall patterns. This lake’s lack of oxygen one meter below the water’s surface has left its sediment in a uniquely undisturbed state. Because of this, and a high accumulation rate, the sediment provides a record of the rainfall in the Solomon Islands over the last millennium. Lipids are well-preserved in sediment over geologic time, making them an ideal proxy for reconstructing tropical paleoclimate. The lipid dinosterol is produced primarily by a limited group of dinoflagellate microalgae and acts as a “molecular fossil”. The isotopic ratio of deuterium to hydrogen (2H/1H) found in dinosterol reflects the 2H/1H ratio in the lake water, which is dictated by changes in precipitation and evaporation. In the tropics, more rain results in 2H-depleted rain and lake water. After purifying dinosterol from the sediment with column chromatography and high-performance liquid chromatography, we found minor fluctuations in the dinosterol 2H/1H ratios, which implies a fairly stable rainfall pattern at this location during the past millennium.
 

Newborns and children are more vulnerable to xenobiotics (foreign chemical substances) partly because little is known regarding the developmental regulation of drug-processing genes (DPGs) by drugs and environmental chemicals. The xenobiotic-sensing nuclear receptors, namely the pregnane X receptor (PXR) and constitutive androstane receptor (CAR), are well-known to up-regulate many DPGs in liver. However, relatively less is known regarding the effect of developmental exposure to PXR- or CAR-activators on the expression of DPGs in intestine, where the biotransformation of orally-exposed xenobiotics takes place. Therefore, the goal of this study was to determine both the acute and the potential long-term effects of neonatal exposure to PXR- and CAR-activators on the regulation of DPGs in neonatal and adult intestine. Wild-type mice were pharmacologically administered the PXR-ligand PCN (the activator of PXR in mice), the CAR-ligand TCPOBOP (the activator of CAR in mice), or vehicle, at 3-day-old neonatal age. Intestines were collected 24h post-dose (whole intestine) or at 60-day-old adult age (duodenum, jejunum, ileum, and colon). Neonatal exposure to TCPOBOP and PCN up-regulated many DPGs 24h postdose. Interestingly, at 60-days adult age, neonatal exposure to TCPOBOP persistently up-regulated many DPGs especially in small intestine, but down-regulated particularly in colon (large intestine). Neonatal exposure to PCN persistently up-regulated 6 DPGs but down-regulated 11 DPGs in specific sections of intestine. In conclusion, this study has demonstrated that neonatal exposure to xenobiotics that activate PXR and CAR not only produce acute induction effect on the DPG expression in newborns, but also lead to persistent alterations on the expression of certain DPGs in adult intestine, and this may potentially alter the pharmacokinetics of orally-exposed chemicals in adults.

Xenobiotic biotransformation is a vital process in the body that detoxifies various drugs, dietary factors, and environmental toxicants. This process is mediated by various drug-metabolizing enzymes in Phase-I (oxidation, reduction, and hydrolysis) and Phase-II, as well as transporters. The hepatic nuclear factor 4alpha (HNF4α) is a master regulator that transcriptionally up-regulates a wide spectrum of drug-metabolizing enzymes and transporters in liver. HNF4α also plays an important role in liver development and nutrient homeostasis. Previously, it has been shown that HNF4α can trans-activate the constitutive androstane receptor (CAR), which is a major ligand-activated xenobiotic-sensing nuclear receptor. However, very little is known about the effect of CAR activation by xenobiotics on the regulation of HNF4α in liver. In the present study, male mice at either 5-day-old neonatal age or 60-day-old adult age in wild-type, CAR-null, or humanized CAR-transgenic (hCAR-TG) genotypes were treated with vehicle (corn oil, which served as the control), or a species-appropriate CAR ligand (TCPOBOP for mouse CAR and CITCO for hCAR), once daily for 4 days. A novel truncated coding exon 9 was observed for the HNF4α transcript variant in mouse liver (RNA-Seq). Isoform-specific RT-PCR and gel electrophoresis confirmed the presence of the novel HNF4α isoform. During development, both the known and the novel isoform had increased expression with age. The mouse CAR ligand, TCPOBOP, down-regulated HNF4α in a mouse CAR-dependent manner only at mice at age 60, whereas hCAR did not appear to regulate the expression of HNF4α at any ages. In conclusion, the present study has identified a novel HNF4α transcript variant in the mouse liver, and discovered that both the known and novel isoforms were regulated by CAR in a species and age-specific manner.

Photosynthesis is how plants gather energy from the sun and store it as chemical energy. This pathway involves multiple energy gathering antennae that absorb light and move electrons through photosystems to store the energy in NADPH and ATP and in turn split water into O₂ and 2H₂. There are two mechanisms proposed for the O-O bond forming step catalyzed by the oxygen evolving complex (OEC), Mn^dang-CaMn₃O₅, of photosystem II, and the dangling Mn (Mn^dang) and Ca ions have both been shown to be involved. One mechanism is through nucleophilic attack by an OH^- that is coordinated to the Ca ion at an electrophilic Mn(V)≡O species, and the other is through radical coupling between two Mn(IV)-O• species. Recent data shows that the nucleophilic attack mechanism is the most likely mechanism. Because the O-O bond forming step occurs after the rate-determining step, these intermediates are not observable in photosystem II. This project involves the synthesis and isolation of species that are representative of the Mn^dang-O-Ca fragment, and intermediates involved in one of the proposed mechanisms for O-O bond formation by the OEC. We are using [Mn(II)(N₃S^Me2(tren))]⁺ as our Mn starting material, and [(dipp-DAD)Ca²⁺(OH)₂]^2- as Ca-(OH)₂ source. The reaction between these two compounds will be monitored by UV-Vis, in the presence of an oxidant, to detect changes in the Mn ion’s electronic environment. So far we have been able to isolate the previously reported [(dipp-DAD)Ca²⁺(THF)₃] precursor complex, and our next step will be to generate hydroxide derivative and monitor its reaction with [Mn(II)(N₃S^Me2(tren))]⁺ using the method described above.

Sediment cores were collected from White Lake (15°2.46' S 167°5.35' E) and Red Lake (15°1.97' S 167°5.40' E), located on Thion Island, Vanuatu, to analyze precipitation patterns in the South Pacific Convergence Zone (SPCZ) during the last millennium. The SPCZ is a poorly understood and understudied region of the Tropical Pacific, with a very short instrumental record of rainfall. Extending the record of natural variability in precipitation is important for assessing future risks of freshwater availability to islands in the tropical pacific. Known for high precipitation rates and spanning 3000 km in a NW to SE orientation, the South Pacific Convergence Zone is the most prominent rainfall feature in the Southern Hemisphere. These freshwater lakes contain the dinoflagellate sterol, dinosterol, which acts as a “molecular fossil” or lipid biomarker and is used to infer variations of the deuterium/protium (²H/¹H) isotopic ratio of the lake water over time since algal lipids track changes in environmental water. The fluctuations in the ²H/¹H ratio in both the lake water and dinosterol are linked to changes in SPCZ precipitation since in the tropics, the rainfall rate is correlated with the isotopic composition of rain. Dinosterol was purified using column chromatography and High Performance Liquid Chromatography, identified and then quantified using Gas Chromatography-Mass Spectrometry and Gas Chromatography-Flame Ionization Detection. The ²H/¹H ratio of the purified dinosterol was determined using Gas Chromatography-Isotope Ratio Mass Spectrometry.

Anthropogenic carbon dioxide (CO₂) has been identified as a primary driver of climate change, the oceans have been shown to be a large sink of this CO₂. Fjord systems have been identified as potential sinks for the CO₂ in summer due to high primary production, but also in winter due to cool surface waters. Our study focuses on the temperate fjord system of Nootka Sound, BC, Canada, during December 2015. Investigation of this precipitation driven fjord system during a strong El Niño may help us to understand the impacts that warming oceans have on the ability of fjords to act as sinks for atmospheric CO₂. Depth profiles at 12 stations began outside of Nootka Sound and went into the head of Muchalat Inlet. Vertical profiles and water samples at 5 depths were collected using the CTD rosette system onboard the R/V Thomas G. Thompson. Additional samples from the surface 10cm of the water column were collected within 2 of the inner fjords, Muchalat and Tahsis. Analysis of these samples for dissolved inorganic carbon (DIC) and alkalinity allowed for the calculation of pCO₂, a measure of the partial pressure of CO₂ in water. From this and atmospheric pCO₂ data provided by Environment Canada, the flux of CO₂ across the air-sea interface was calculated. Preliminary results of surface samples show effluxes of CO₂ near riverine inputs, while surface waters within the inlets appear to be in near equilibrium with the atmosphere. Preliminary transect results show deep waters have higher pCO₂, further analysis will reveal if a relationship between air-surface fluxes and deep water exists.

The oxygen evolving complex (OEC) is the enzyme in Photosystem II responsible for oxidizing water into oxygen gas. The OEC, a Mn₄O₅Ca cofactor, has one manganese “dangling” off a cubane, and it undergoes several conformational changes as photons provide energy for the splitting of water. The mechanisms and intermediates for the transitions between states are not fully understood, so research into manganese dioxygen chemistry will illuminate this important biological process. In order to characterize intermediates more successfully, we use synthetic, small molecule, ligand framed analogues that emulate the properties of the enzyme. Synthetic analogues have a distinct advantage in characterizing intermediates because the enzyme is limited to activity under conditions of a living organism such as temperature and solvent. By tuning the conditions and coordination sphere of our manganese complexes, we can stabilize metastable intermediates in order to spectroscopically characterize them. Our target is to synthesize a mononuclear manganese superoxo complex modeling the dangling manganese, which has been previously reported as an active site in oxygen evolution. A superoxo must be the last intermediate in oxygen evolution, so by characterizing our complex, we can determine viable mechanisms for the evolution of oxygen off the dangling manganese. We designed the ligand to be sterically bulky and have a low coordination number so there is a selective open coordination site for dioxygen binding. The lower coordination number raises the manganese’s Lewis acidity which allows for reversible oxygen binding. A trans thiolate is incorporated into the ligand framework as it has been previously shown that the sulfur to metal charge transfer band is in the visible region, giving the complex an easily identifiable spectroscopic property. By synthesizing our superoxo complex then characterizing its properties, we can better understand the complex mechanisms of oxygen evolution.

This research is focused on a high school career and technical education program about translation and interpretation (T & I) for bilingual students. Our research evolved around the question: “How does the T & I program and its service-learning component change students’ language ideologies and understanding of their own skills.” We have used an ethnographic approach in able to answer the research question. We have collected data from student interviews and class visits as well as analyzed teaching methods used in classes. Many students have experienced hardships and oppressions in their local high schools because they are bilingual. By taking the T&I class, students have developed confidence about their language skills and started to treat bilingualism as an asset that will help them in the professional world. Many students have shown significant improvement in vocabularies in their native language and they are more willing to translate for their parents because they have witnessed a space where it is valuable to be bilingual. Students that graduated from this program have decided to either pursue a college degree or choose a career related to translation even though it may not be their original intention before joining the program. We believe that similar program in other schools throughout the country should be implemented in order to help high school students achieve better future.