As the world population ages, hospital discharges of geriatric patients to nursing homes have increased. Patients with peripherally inserted central catheters (PICCs) are routinely discharged with the catheters in place. PICCs, only capable of being tracked through x-ray imaging, will routinely experience complications due to thrombosis or accidental dislodgement from poor at-home care. Routinely, elderly patients will be forced to revisit the hospital to have the catheter replaced using x-ray imaging, exposing them to hospital borne illness. Catheters with the capability to be tracked without the need of x-ray imaging would greatly benefit the ill and elderly, providing decreased stress to the patients and increase nursing home capabilities. This project seeks to develop the field of real-time ultrasound tracking of polymeric medical devices, through fabrication of ultrasound responsive polymer-glass composites. Optimal composition will be researched through three complimentary approaches. The first approach seeks to develop a polyurethane-glass microparticle composite to understand the relationship between microparticle loading and ultrasound imaging. In the second approach, manufacturing and end-use complications will be simulated to evaluate the effects on mechanical and ultrasonic properties. Furthermore, impacts from in-vitro long term catheterization to the sample mechanical and ultrasound morphologies would be analyzed. In the third approach, optimization from the previous approaches would assist in the replacement of medical grade polyurethane with medical grade thermoset silicone in hopes to prove the ability for the research to be transferable to other medical polymeric devices. The stated approaches will be useful for setting a path towards the development of ultrasonic imaging as the standard for medical device tracking. / Doctor of Philosophy / As the world population ages, hospital discharges of geriatric patients to nursing homes have increased. Patients with peripherally inserted central catheters (PICCs) are routinely discharged with the catheters in place. PICCs, only capable of being tracked through x-ray imaging, will routinely experience complications due to poor at-home care. Routinely, elderly patients will be forced to revisit the hospital to have the catheter replaced using x-ray imaging, exposing them to hospital borne illness. Catheters with the capability to be tracked without the need of x-ray imaging would greatly benefit the ill and elderly, providing decreased stress to the patients and increase nursing home capabilities. We hope to develop the field of real-time ultrasound tracking of plastic medical devices, through production of ultrasound activated plastic devices.

Plant mitochondrial genomes are large and complex, and the mechanisms for maintaining mitochondrial DNA (mtDNA) remain unclear. Arabidopsis thaliana has two DNA polymerase genes, polIA and polIB, that have been shown to be dual localized to mitochondria and chloroplasts but are unequally expressed within primary plant tissues involved in cell division or cell expansion. PolIB expression is observed at higher levels in both shoot and root apexes, suggesting a possible role in organelle DNA replication in rapidly dividing or expanding cells. It is proposed that both polIA and polIB are required for mtDNA replication under wild type conditions. An Arabidopsis T-DNA polIB mutant has a 30% reduction in mtDNA levels but also a 70% induction in polIA gene expression. The polIB mutant shows an increase relative to wild type plants in the number of mitochondria that are significantly smaller in relative size, observed within hypocotyl epidermis cells that have a reduced rate of cell expansion. These mutants exhibit a significant increase in gene expression for components of mitorespiration and photosynthesis, and there is evidence for an increase in both light to dark (transitional) and light respiration levels. There is not a significant difference in dark adjusted total respiration between mutant and wild type plants. Chloroplast numbers are not significantly different in isolated mesophyll protoplasts, but mesophyll cells from the mutant are significantly smaller than wild type. PolIB mutants exhibit a three-day delay in chloroplast development but after 7dpi (days post-imbibition) there is no difference in relative plastid DNA levels between the mutant and wild type. Overall, the polIB mutant exhibits an adjustment in cell homeostasis, which enables the maintenance of functional mitochondria but at the cost of normal cell expansion rates.

No description available.

Ribonucleotide reductase (RNR) is a key enzyme for de novo dNTP biosynthesis. We have studied nucleotide-dependent oligomerization of the allosterically regulated mammalian RNR using a mass spectrometry–related technique called Gas-phase Electrophoretic Mobility Macromolecule Analysis (GEMMA). Our results showed that dATP and ATP induce the formation of an α6β2 protein complex. This complex can either be active or inactive depending on whether ATP or dATP is bound. In order to understand whether formation of the large complexes is a general feature in the class Ia RNRs, we compared the mammalian RNR to the E. coli enzyme. The E. coli protein is regarded a prototype for all class Ia RNRs. We found that the E. coli RNR cycles between an active α2β2 form (in the presence of ATP, dTTP or dGTP) and an inactive α4β4 form in the presence of dATP or a combination of ATP with dTTP/dGTP. The E. coli R1 mutant (H59A) which needs higher dATP concentrations to be inhibited than the wild-type enzyme had decreased ability to form these complexes. It remains to be discovered how the regulation functions in the mammalian enzyme where both the active and inactive forms are α6β2 complexes. An alternative way to produce dNTPs is via salvage biosynthesis where deoxyribonucleosides are taken up from outside the cell and phosphorylated by deoxyribonucleoside kinases. We have found that the pathogen Trypanosoma brucei, which causes African sleeping sickness, has a very efficient salvage of adenosine, deoxyadenosine and adenosine analogs such as adenine arabinoside (Ara-A). One of the conclusions made was that this nucleoside analog is phosphorylated by the T. brucei adenosine kinase and kills the parasite by causing nucleotide pool imbalances and by incorporation into nucleic acids. Ara-A-based therapies can hopefully be developed into new medicines against African sleeping sickness. Generally, the dNTPs produced from the de novo and salvage pathways can be imported into mitochondria and participate in mtDNA replication. The minimal mtDNA replisome contains DNA polymerase γA, DNA polymerase γB, helicase (TWINKLE) and the mitochondrial single-stranded DNA-binding protein (mtSSB). Here, it was demonstrated that the primase-related domain (N-terminal region) of the TWINKLE protein lacked primase activity and instead contributes to single-stranded DNA binding and DNA helicase activities. This region is not absolutely required for mitochondrial DNA replisome function but is needed for the formation of long DNA products.

在國際時尚舞台中，台灣在過去一直扮演代工的角色：儘管手中握有無與倫比的研發與生產技術，然而報酬率卻遠不及握有「國際品牌」的廠商。 1990年起，台灣以往勞力、技術密集的紡織產業開始走下坡。台灣紡織產業開始面臨勞工短缺、工資上漲，許多低價紡織品在國內生產已無獲利空間；從2000年左右開始，隨著全球化市場發展，中國大陸與東南亞等新興國家陸續崛起，我國紡織產業開始產生外移。2005年，WTO協定生效，取消「紡織貿易配額」，以及全球各地逐漸形成的「區域經濟體」，使得全球紡織產業發生結構性的變化。 近來「美學經濟」指標性產業：「時尚產業」，已經成為亞洲國家積極發展的目標，而政府也大力鼓吹由過去專業代工的「製造經濟」，轉型為以品牌、設計為主的「創意、知識經濟」。2008年國家重點發展計畫中提出「產業高值化」政策，除了研發，強化行銷能力以提升品牌知名度亦是創造高附加價值的重要關鍵。 台灣在本土時裝設計師品牌不少。然而，礙於台灣市場規模，始終無法有大幅的成長。因此，台灣設計師如何進軍國際市場，便成了一個值得深入探討的議題。 本研究結合Csikezentmihalyi創造力系統模式、與設計師日常事業經營，探討本土設計師時裝品牌國際化的動態過程：設計師如何以服裝設計專業、結合創業營運相關知識，不斷與國際時尚界專業人士與買家們溝通互動，進而使其品牌在國際間佔有一席之地。 本研究同時歸納設計師在進軍國際市場時需要哪些能力，以及在進入國際市場不同階段所應注意的管理議題，期望能供業界、後續學術研究參考、指教。 / This research is about how Taiwanese fashion designers market their products internationally. Taiwanese textile companies didn’t have their own brands before. They mainly manufactured and sold products overseas under foreign brand names. However, the textile manufacturing industry in Taiwan has already moved abroad to low-labor-cost area during the past two decades. Taiwanese designer brands have been struggleing between the small domestic market and the competition of foreign brands. I explored three cases of Taiwanese fashion designers who market their brands and products internationally. They are respectively Hong, Li Fen’s designer brand ‘Sophie Hong’, Chien, Yu Feng and Pan, Po Shun’s ‘Shawnyï’, and Chia, Wen Lan’s ‘Twinkle by Wenlan’. I analyzed these cases based on the Creativity Dynamic System Model (Csikezentmihalyi, 1990). First, I discovered how they combine their expertises of fashion design and business management to organize their international network. Second, the abilities a fashion designer has to possess during his way to international fashion market have already been clearly listed and categorized. In the end, I casted several managerial issues the fellow designers should pay attention to in different stages when they try to internationalize their brands and products.