Micropatterned carbon nanotube embedded cell-laden gelatin methacrylate hybrid hydrogels for cardiac tissue

Thesis (M.A.)--Boston UniversityCardiovascular disease is the leading cause of mortality in the world. Cardiac tissue engineering promises to replace damaged organs and tissues with biologically compatible engineered substitutes. Micro- and nanotechnologies have proven to be effective to address current challenges in tissue engineering and regenerative medicine. A principle approach in tissue engineering is the integration of innovative biomaterials with micro- and nanofabrication techniques to generate constructs that recapitulate the in vivo cellular microenvironments. In this study, highly organized three-dimensional (3D) cardiac tissue constructs in carbon nanotube (CNT) embedded gelatin methacrylate (GelMA) were generated using micropatterning techniques. Neonatal rat ventricular cardiomyocytes (NRVMs) and cardiac fibroblasts (CFs) were used as the primary cardiac cell types to be encapsulated in the three-dimensional tissue constructs. The resulting cardiac constructs in CNT-GelMA hybrid hydrogels from various methods showed enhanced cell viability and higher spontaneous synchronous beating rates, compared to those in pristine GelMA hydrogels. Further studies are necessary to determine the efficacy of micropatterned 3D cardiac tissue constructs in CNT-GelMA hybrid hydrogels for in vitro studies and therapeutic purposes

Korea\u27s New Prostitution Policy: Overcoming Challenges to Effectuate the Legislature\u27s Intent to Protect Prostitutes from Abuse

Prostitution has been rampant in South Korea, exposing tens of thousands of women to abuse and violence. Beginning in 2000, however, women’s rights organizations spearheaded a legal reform campaign to change the nation’s prostitution policy. They drafted and proposed two bills to the National Assembly, which subsequently enacted them as laws. In passing the new legislation, the South Korean government vowed to eliminate prostitution as well as protect victims of exploitation and violence in the sex industry. However, the legislation fails to achieve these goals due to inherent inadequacies in the language and structure of the laws. This shortfall arises because the government failed to adequately discuss the breadth and depth of prostitution’s impact on Korean men and women. Consequently, the legislation retains a discriminatory attitude towards prostituting women and still criminalizes them unless they can prove their victim status. It is doubtful that these provisions can protect abused women in the sex industry, particularly when they face so many barriers in proving their victim status. To remedy these problems, the South Korean government must reconsider and rework its prostitution policy so that it is more protective of women engaged in prostitution and more appropriate for Korean society. It must also rethink enforcement mechanisms to allow prostituting women to seek help when necessary

FROM ESL LEARNERS TO EFL LEARNERS: A CASE STUDY OF ADOLESCENT KOREAN RETURNEES

There are growing populations of Korean parents who wish their children to have a study abroad experience in the ESL (English as a second language) context due to their beliefs that early exposure to an English-speaking environment is beneficial for children’s English proficiency. However, many children return to South Korea before reaching college age for various reasons, and Korean returnees are concerned on how to maintain (or improve) their children’s English proficiency in the EFL (English as a foreign language) context. Although there are some studies related to Korean English language learners’ study abroad experiences and second language acquisition, few studies have been conducted to investigate how study abroad experience influences Korean returnees’ English language learning experience. The purpose of this qualitative case study was to investigate English language learners who recently returned to South Korea after learning English in the U.S. for more than two years. The research questions were as follows: 1) How do Korean returnees perceive the change of learning status from ESL learners to EFL learners, and 2) What characteristics influence the extent to which Korean returnees maintain or lose their English proficiency after having returned to South Korea? The theoretical framework of this dissertation is based on the related literature of second language acquisition (SLA) theories and study abroad (SA) studies. Among second language acquisition studies, second language attrition theories are investigated and specific Korean education backgrounds are introduced. By using a case study method, I provide an extensive and in-depth description of Korean returnees’ English language learning experiences. Data were collected through the researcher’s field notes and semi-structured interviews with five participants and their mother. By analyzing Korean returnees’ perceptions on ESL and EFL learning contexts, this study extends the literature in the field of second language acquisition and contributes knowledge about factors that motivate English language learners to maintain and improve their English proficiency. This study has implications for English language learners within the U.S. and from other countries who struggle to achieve or at least maintain their second language proficiency

Devleopment and application of fluorescent nucleoside

令和2年度 京都大学化学研究所 スーパーコンピュータシステム 利用報告

The Use of Chemical Element Fingerprints to Investigate the Transformation of Lake Sediments to Land Soils in Drying Lakes: A Case Study at Lake Mead, Nevada

Drying lakes are a worldwide catastrophe. The goals of this dissertation research were (1) to investigate whether chemical fingerprints of lake sediments, and nearby land soils, could be established by the analysis of 44 chemical elements, moisture content, Eh, pH, and leachable anions and if so, (2) whether the fingerprints could help explain the process of physical and chemical changes in the lake sediments as they became soils when the lake\u27s water level fell and the anoxic sediments were exposed to the air and weather. Lake Mead was chosen to model drying lakes because its water level has fallen over 150 feet from full pool, stranding acres of former lake sediments to be transformed into land soils. Since the lake was formed, it has experienced three cycles of drying and refilling. This history complicates the chemical fingerprint, but has yielded a new sediment dating method. The research was conducted at Crawdad Cove in Lake Mead, Nevada, from 2012 to 2018. Six soil or sediment cores were collected at three locations along each of two transects on the east and west sides of Crawdad Cove Road at Lake Mead. One core was at the water’s edge and two spaced equidistant going inland from the water’s edge towards the historical full lake water elevation line. Each core was sliced vertically in up to 50 samples. Data were analyzed using ICPAES, ICPMS, XRF, alpha spectrometry, and ion chromatography to examine element concentrations, percent moisture, and anion concentrations and Principal Component Analysis (PCA) to process ten thousands of the experimental results. Most chemical elements, including Mg, Al, P, S, Ca, V, Cr, Ni, Cu, Zn, Rb, Sr, Y, Zr, Ba, La, Ce, Nd, Pb, Th, and U, had their highest concentrations in the submerged sediment core and lower concentrations in the inland soil cores. Higher concentrations of F-, Cl-, and SO42- are found in the water’s edge than the farthest inland and they are strongly correlated to each other. HCO2- and NO3 are higher in the farthest inland core than at the water’s edge. Sulfur by ICP and sulfate by ion chromatography have a strong correlation, as they should. The results of PCA showed that: (1) every cores had an unique fingerprint; and (2) rather than showing a consistent pattern of change in the cores along each transect based on distance from shoreline, the patterns of chemical fingerprint in the cores reflected changes in elevation. The change in chemical fingerprints in the cores is most closely associated with time the sediments have been out of the water. The elevation is the marker of lake sediments’ wetting/drying history due to the changes in lake level. The results of this analysis indicate that there is a clear change in chemical fingerprint as drying lake sediments become soils. The most likely explanation for the chemical fingerprint change is that it reflects changes in the redox conditions from reducing to oxidizing which creates soluble element species. Other explanations are possible if the sediment composition changes over time. This could occur due to factors such as wind erosion or deposition that would change surface material composition, water erosion or deposition of the surface material and vegetation growth in the mudflats after lake water recedes that affects uptake and cycling of chemical elements. Investigation of such factors would be an interesting future extension of this analysis. Core dating or calculating sedimentation rates was done by two methods: one by an established Pb-210 dating and a new method using the historical records of lake water levels and the ratios of the natural abundances of the elements divided by the concentrations of the elements in mid-inland cores from the two transects. Results of these two dating methods agree closely, 0.6 cm/year for the Pb-210 method and 0.7 cm/year for the natural abundance ratio method. This suggests that the historical records and ratio method can substitute well for the Pb-210 dating method. It also suggests that the historical record of sediment input to the lake is somewhat preserved since Lake Mead was created in 1935

Living Curriculum Shifts in Arts Education: From Knowledge Transmission to Worldview Sharing

Drawing upon narrative inquiry into the lived experience of an artist becoming an arts teacher, this research investigates curriculum in arts education. Its focus is the teaching experiences of a professional photographer in the process of becoming a photography teacher. This research began with two teaching assumptions about curriculum. The first was an acquisition-orientation to teaching; knowledge transmission that changes students’ state from unknowing to knowing. The second was a making-orientation to teaching; methods and techniques training that allows students to replicate or produce knowledge. The first emphasized content while the second emphasized how students apply it. These assumptions eventually changed until they emerged as a communication-orientation to teaching that focuses on interaction with students and a sharing-orientation to teaching that engages dialogue between teacher and students instead of teacher monologue. With a communication-orientation and sharing-orientation to teaching, students became curriculum makers rather than curriculum receivers. These shifts in orientation meant students could share “their own stories” together with their own photographs, thus composing valuable narratives for the study—narratives that provided insight into how they see the world. Arts education is not only about transferring knowledge from teacher to students, but about sharing feelings with students. A communicating and sharing curriculum makes possible an encounter of minds between teacher and students, which was conceptualized as “relationship of minds” in this research. It enables us to better understand teaching and curriculum