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

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

Economic Ripple Effect Analysis of New Converging Industry: Focusing on Inter-Industrial Analysis of Fintech Industry in South Korea, China and the United States

116–121The Fintech industry is the convergence of the financial industry and the ICT (Information and Communications Technology) industry. It not only replaces the services provided by traditional financial services such as remittances, settlements, and asset management, but also creates new industries combined with ICT technology such as Cloud funding, P2P, and Internet Professional Bank. Therefore, this research focuses on the economic ripple effect of the Fintech industry on the national economy by inter-industrial analysis. At the same time, in order to learn the different circumstances of Fintech industry worldwide, this study conducted comparative research on Fintech leading countries in the United States and China with South Korea. All the economic ripple effects of South Korea, China, and the United States Fintech industry are relatively low among all industries, and the industrial characteristics are analyzed to be 'intermediate primary production' type industry. This study, as the first attempt, analyzes the current economic impact of Fintech in each country, and inspires future development direction of Fintech industrial policy

Economic Ripple Effect Analysis of New Converging Industry: Focusing on Inter-Industrial Analysis of Fintech Industry in South Korea, China and the United States

The Fintech industry is the convergence of the financial industry and the ICT (Information and Communications Technology) industry. It not only replaces the services provided by traditional financial services such as remittances, settlements, and asset management, but also creates new industries combined with ICT technology such as Cloud funding, P2P, and Internet Professional Bank. Therefore, this research focuses on the economic ripple effect of the Fintech industry on the national economy by inter-industrial analysis. At the same time, in order to learn the different circumstances of Fintech industry worldwide, this study conducted comparative research on Fintech leading countries in the United States and China with South Korea. All the economic ripple effects of South Korea, China, and the United States Fintech industry are relatively low among all industries, and the industrial characteristics are analyzed to be 'intermediate primary production' type industry. This study, as the first attempt, analyzes the current economic impact of Fintech in each country, and inspires future development direction of Fintech industrial policy

Ninjurin1 positively regulates osteoclast development by enhancing the survival of prefusion osteoclasts

Osteoclasts (OCs) are bone-resorbing cells that originate from hematopoietic stem cells and develop through the fusion of mononuclear myeloid precursors. Dysregulation of OC development causes bone disorders such as osteopetrosis, osteoporosis, and rheumatoid arthritis. Although the molecular mechanisms underlying osteoclastogenesis have been well established, the means by which OCs maintain their survival during OC development remain unknown. We found that Ninjurin1 (Ninj1) expression is dynamically regulated during osteoclastogenesis and that Ninj1(-/-) mice exhibit increased trabecular bone volume owing to impaired OC development. Ninj1 deficiency did not alter OC differentiation, transmigration, fusion, or actin ring formation but increased Caspase-9-dependent intrinsic apoptosis in prefusion OCs (preOCs). Overexpression of Ninj1 enhanced the survival of mouse macrophage/preOC RAW264.7 cells in osteoclastogenic culture, suggesting that Ninj1 is important for the survival of preOCs. Finally, analysis of publicly available microarray data sets revealed a potent correlation between high NINJ1 expression and destructive bone disorders in humans. Our data indicate that Ninj1 plays an important role in bone homeostasis by enhancing the survival of preOCs

High resolution crystal structure of PedB: a structural basis for the classification of pediocin-like immunity proteins

<p>Abstract</p> <p>Background</p> <p>Pediocin-like bacteriocins, ribosomally-synthesized antimicrobial peptides, are generally coexpressed with cognate immunity proteins in order to protect the bacteriocin-producer from its own bacteriocin. As a step for understanding the mode of action of immunity proteins, we determined the crystal structure of PedB, a pediocin-like immunity protein conferring immunity to pediocin PP-1.</p> <p>Results</p> <p>The 1.6 Å crystal structure of PedB reveals that PedB consists of an antiparallel four-helix bundle with a flexible C-terminal end. PedB shows structural similarity to an immunity protein against enterocin A (EntA-im) but some disparity to an immunity protein against carnobacteriocin B2 (ImB2) in both the C-terminal conformation and the local structure constructed by α3, α4, and their connecting loop. Structure-inspired mutational studies reveal that deletion of the last seven residues of the C-terminus of PedB almost abolished its immunity activity.</p> <p>Conclusion</p> <p>The fact that PedB, EntA-im, and ImB2 share a four-helix bundle structure strongly suggests the structural conservation of this motif in the pediocin-like immunity proteins. The significant difference in the core structure and the C-terminal conformation provides a structural basis for the classification of pediocin-like immunity proteins. Our mutational study using C-terminal-shortened PedBs and the investigation of primary sequence of the C-terminal region, propose that several polar or charged residues in the extreme C-terminus of PedB which is crucial for the immunity are involved in the specific recognition of pediocin PP-1.</p

CHANGE IN SPATIOTEMPORAL CYCLE VARIABLES & MUSCLE ACTIVATION DURING CtASSlC ROLLER SKI DOUBLE POLING TECHNIQUE

The purpose of the study was to assess the effects of distance covered while roller skiing using the double poling technique. Five national team members and college elite cross-country skiers were chosen to participate in this study. EMG system and digital camcorder were used to measure spatiotemporal cycle variables, muscular fatigue, and activation patterns. There were no significant differences on cycle variables. However, the result shows accumulation of fatigue and decrease of muscle activation on triceps brachii and tibialis anterior muscles across skiing distance

Therapeutic effects of phlorotannins in the treatment of neurodegenerative disorders

Phlorotannins are natural polyphenolic compounds produced by brown marine algae and are currently found in nutritional supplements. Although they are known to cross the blood–brain barrier, their neuropharmacological actions remain unclear. Here we review the potential therapeutic benefits of phlorotannins in the treatment of neurodegenerative diseases. In mouse models of Alzheimer’s disease, ethanol intoxication and fear stress, the phlorotannin monomer phloroglucinol and the compounds eckol, dieckol and phlorofucofuroeckol A have been shown to improve cognitive function. In a mouse model of Parkinson’s disease, phloroglucinol treatment led to improved motor performance. Additional neurological benefits associated with phlorotannin intake have been demonstrated in stroke, sleep disorders, and pain response. These effects may stem from the inhibition of disease-inducing plaque synthesis and aggregation, suppression of microglial activation, modulation of pro-inflammatory signaling, reduction of glutamate-induced excitotoxicity, and scavenging of reactive oxygen species. Clinical trials of phlorotannins have not reported significant adverse effects, suggesting these compounds to be promising bioactive agents in the treatment of neurological diseases. We therefore propose a putative biophysical mechanism of phlorotannin action in addition to future directions for phlorotannin research