Doping Modification and Ceramization of Hyperbranched Polycarbosilanes

聚合物先驱体陶瓷法(PDC)由于拥有众多优点已成为制备高性能陶瓷的重要方法。聚碳硅烷(PCS)作为SiC基陶瓷的聚合物先驱体方面的研究已引起广泛关注。其中，一种超支化聚碳硅烷(HBPCS)由于其超支化结构，低粘度，可溶，较多的活性官能团等优点，适用于PDC法制备SiC基陶瓷复合材料而备受青睐。目前，在SiC基陶瓷中引入异质元素从而赋予陶瓷优异的电磁性能，成为高性能陶瓷研究的热点。 本论文以HBPCS为原料，合成了含钛、锆、铁的杂化先驱体，经交联裂解得到了含钛、锆、铁的SiC基复合陶瓷。采用傅立叶红外光谱(FTIR)、核磁共振谱(NMR)、凝胶渗透色谱(GPC)等测试方法分析先驱体的化学结构、...The polymer derived ceramic (PDC) route has been considered as one of the most popular methods to prepare silicon carbide (SiC) based ceramic composites for its advantages. Polycarbosilanes (PCSs) have been of particular interest as precursors to SiC. Of all the PCSs, a hyperbranched polycarbosilanes (HBPCS) maybe regarded as excellent precursors for SiC ceramic matrix sources because of their uni...学位：理学硕士院系专业：材料学院材料科学与工程系_高分子化学与物理学号：2072008115057

低氧含量液态超支化聚碳硅烷的合成与陶瓷化研究

以甲醇对氯甲基三氯硅烷(Cl3SiCH2Cl)进行烷氧化反应,然后经过格氏偶联反应和还原反应,制备了低氧含量液态超支化聚碳硅烷(HBPCS)。通过凝胶渗透色谱法(GPC)、核磁共振(NMR)以及元素分析对由此制备的HBPCS进行表征。结果表明,提高烷氧化比例,可以有效抑制溶剂四氢呋喃开环的副反应,降低先驱体氧含量。通过热失重分析(TGA)和X射线衍射(XRD)分别对HBPCS的热性能及相应陶瓷在高温下的结晶行为进行研究

偶氮二异丁腈引发液态聚碳硅烷的交联研究

在偶氮二异丁腈(2,2′–azobisisobutyronitrile,AIBN)引发下,研究液态超支化聚碳硅烷(hyperbranched polycarbosilane,HBPCS)的无氧热交联,考察交联温度、AIBN用量以及时间对交联反应及陶瓷产率的影响。结果表明:较高的温度可促进交联;AIBN用量越多越有利于交联,陶瓷产率先增加而后稳定,其最佳用量为1.0%～2.0%(质量分数,下同);随着交联时间延长,HBPCS的交联程度和陶瓷产率先增加而后保持不变。对于AIBN用量1.5%的体系,HBPCS经80℃交联6h后,其1000℃下的陶瓷产率高达75%以上。此外,对最终陶瓷相组成进行表征,发现AIBN的引入能够有效抑制β-SiC的结晶

液态超支化聚碳硅烷的研究进展

液态超支化聚碳硅烷(HBPCS)因具良好的流动性和可自交联性,适用于制备SiC陶瓷基复合材料而倍受青睐。对它的合成、交联、陶瓷化和应用探索等方面的研究动态进行了综述,并展望了其今后的发展趋势

过氧化苯甲酰在液态聚碳硅烷交联中的应用

聚碳硅烷热解前的交联对于提高其最终陶瓷产率至关重要。研究了过氧化苯甲酰(BPO)引发液态超支化聚碳硅烷(HBPCS)的交联反应对于陶瓷产率的影响。FT-IR和GPC证实,添加为0.5%～2.0%(质量分数,下同)的BPO,即可在80～140℃下引发HBPCS交联;在考察的实验条件下,提高交联温度、延长反应时间或增加BPO用量,均可提高HBPCS交联程度。BPO用量为2.0%时,HBPCS交联样品在1000℃下的陶瓷产率高达65%,比未加BPO的提高25%

水稻高附加價值基因轉殖之研究

1.Selectable markers enable transgenic plant or cells to be identified after transformation. In this project, we construct a plasmid vector carried novel marker gene, racemase gene, which mediate the racemization of selective agents and can be applied as an alternative selection marker instead of antibiotic resistance gene in screening system of transgenic plant. This antibiotic-free screening system will reduce the impaction of antibiotic gene of the environment and increase the safety of food. 2.The aim of this study is to develop the daao gene from T. variabilis as a selectable marker in transgenic plants. The demand of both research and commercial crop production eads to explore new biosafety selectable markers and develop strategies for generate marker-free plants become an area that is growing rapidly. Our preliminary results indicated that the ability of E. coli JM109 to grow on M9 medium containing Dasparagine as sole nitrogen source required DAAO expression. The potential of using T. variabilis daao as a selectable marker in transformed bacteria will be evaluated in the ongoing project. In our previous study, two plant expression plasmids, designated as pCaPDAO and pRPDAO, each has T. variabilis daao under the control of CaMV35S and rbcS promoter, respectively, were constructed. The constructed pCaPDAO and pRPDAO plasmids had been transferred into callus of rice (Oryza sativa L. cv. Tinung 67) via Agrobacterium-mediated transformation. Several regenerated plants were then selected by antibiotic G418. The presence of daao in the transgenic plants was confirmed by PCR in our preliminary studies. Moreover, the toxicity of D-amino acid on rice germination was evaluated by plating on half-strength MS medium containing different concentration of D-alanine or D-serine. Growth inhibition was observed for medium containing 10 ppm of D-alanine. To successfully establish daao as selectable marker in transgenic rice, expression vectors with both of the daao and gus or gfp 3.Neisseria meningitidis is a capsulated Gram-negative bacterium causing meningitis and septicemia, the life-threatening invasive infections, and is therefore a potential bioweapon. To meet emergent needs in cases sufficient stock of the vaccines including antisera for passive immunization is necessary. Since the findings by E. A. von Behring showing that specific antisera was effective in curing diphtheria, antibodies have been the solving to the poisoning from bites by snakes or spiders and acteremia or septicemia caused by gram-negative bacteria. One of the bottleneck in application of antibodies in medicine is the high costs in production. As a major crop in Taiwan, rice has the potential to be used as a bioreactor for antibody production so as to decrease the cost of production and increase the value of this crop. The final goal of this project is to construct transgenic rice plants for the production of antibodies and vaccines against N. meningitidis, with production of antibody 4-7-3 and the cognate antigen Ag473 being the first goal. Development of bioindustry in Taiwan has been lagged and is moving slowly, and therefore the intellectual property rights has been relatively narrow. The hybridomas and Ag473 used in this research are all original and has no problem in violating the intellectual property rights. In contrast, our invention can file patents in different countries. In addition, our research can consolidate our agriculture and medical biotech industries. The antibodies obtained from our work can be used, in place of antibiotics, to treat N. meningitidis, as well as to prevent the invasion of this organism. They can also be used to develop diagnostic kits and for strain classification. Success in t1.建立一個以racemase基因為篩選標記的表現載體，應用於異源性蛋白表現系統開發新的水稻基因轉殖篩選系統，此系統是利用racemase的生物轉換特性對篩選劑進行消旋作用以達到植物選殖目的，並降低對生態環境的衝擊及增加基改食物的安全性。 2.本研究的目的是希望能建立由T. variabilis 菌株來源的daao基因，作為水稻或其它作物的篩選標誌。因為發展安全性篩選標誌基因或無篩選標誌基因的轉殖植物，是目前研究及應用上的趨勢。我們在上一年度的研究中，先以大腸菌菌株進行測試，發現在添加有0.08%及0.12% D-Asparagine 作為氮源的M9 基礎培養基中，僅經轉型帶有T. variabilis daao基因質體的大腸菌株才會生長，說明了daao基 因具有作為大腸菌株篩選標誌基因的潛力。為便利轉殖水稻的分析及篩選工作，在上一年度工作中，我們亦已完成了兩個可以在水稻表現載體pCaPDAO 及 pRPDAO的構築，它們分別具有可受CaMV35S 及rbcS 啟動子調控之T. variabilis daao 基因。此兩個植物表現載體也初步藉由農桿菌轉殖法，轉殖到水稻癒傷組織，並誘導再生。目前已初步完成G418抗生素的篩選及PCR分析工作。此外，將水稻種子播種於添加有不同濃度D-alanine或D-serine 的1/2 MS培養基中，發現10 ppm以上濃度的D-alanine 即可對水稻種子的發芽產生抑制作用。在這一年度的工作中，我們將先完成在同一載體上，同時具有可受CaMV35S 及rbcS 啟動子調控之daao基因及gus或gfp 報導基因表現載體的構築，以便利水稻轉殖株的分析及篩選工作。並將繼續利用D-alanine或D-serine對帶有daao基因的水稻轉殖株進行測試，最後利用 3.奈瑟氏腦膜炎雙球菌(NM)為具有頰膜的格蘭氏陰性菌，會引起腦脊髓膜炎、菌血症及敗血病，是一個潛在的生物性武器。為了因應不時之需，應儲備足夠的疫苗(包括作為被動疫苗之抗體)。自Emil A. von Behring證明抗白喉血清可用來治療白喉以來，抗體是治療毒蛇或毒蜘蛛咬傷及格蘭氏陰性菌所造成之菌血症及敗血症的救命解藥。抗體在臨床醫學應用上最大的瓶頸在於生產成本過高，水稻為台灣 主要的農產作物，若能以水稻作為抗體生產之生物反應器，不但能降低抗體之生產成本，更能提昇水稻之經濟價值。本計畫的最終目標是建立轉殖水稻生產抗奈瑟氏腦膜炎雙球菌抗體以及疫苗；其中以生產抗體4-7-3及其抗原Ag473為首要目標。 台灣生技產業起步較晚，速度較慢，而因智慧財產權的限制，使台灣的研發空間更形狹小。本研究所使用的融合瘤細胞及抗原均為自行研發之成果，無侵犯智慧財產權之虞，因此可以申請全世界各國專利。另外，藉由此研究結果，結合台灣農業與醫學生物科技，使水稻生產抗體及疫苗成為台灣生技產業特色之一。本研究所得到的抗體可替代抗生素作為治療奈瑟氏腦膜炎雙球菌所造成之菌血症、預防奈瑟氏腦膜炎雙球菌由鼻腔進入血液循環系統入侵腦組織造成腦膜炎、以及 用來研發診斷試劑或流行感染病學之菌種分類；而Ag473具有成為腦膜炎雙球菌疫苗成份，本計劃成果將提升台灣在抗體與疫苗生技產業的競爭力。 4.轉穀氨醯胺酵素(Transglutaminase, TGA)廣泛分布於大部份的動物組織和體液，並且與許多生命現象有關，如血液凝固、傷口癒合、表皮角質化和紅血球細胞膜變硬等。除了動物之外，轉穀氨醯胺酵素也存在於植物、魚類及微生物中。轉穀氨醯胺酵素會使蛋白濃縮液形成膠體化，因此在食品加工上有相當高的應用價值及潛力；例如：在漢堡、肉丸、魚漿、豆腐、植物蛋白粉末等可改善彈性、質地、口感、風味，並可增加儲存壽命。目前轉穀氨醯胺酵素大多自動物肝臟中分離純化取得，由於來源取得不易且分離純化過程複雜，使得轉穀氨醯胺酵素的價格相當高，一單位約八十美元，因此限制了其在食品加工上之應用。目前轉穀氨醯胺酵素在日本之年銷售顯達二十億日圓以上。L-homophenylalanine (L-HPA)為廣泛被使用在降血壓藥物的合成，以往多是以化學方法合成，除了費時，價格昂貴外，也會造成環境污染等問題，近年來有開發以酵素生產L-HPA。N-acylamino acid racemase (消旋酵素, NAAAR)在生產L-HPA上扮演提高原料轉換率、大幅降低成本的關鍵性角色。中興大學分子生物研究所楊明德博士及許文輝博士的實驗室已篩選出tga及naaar基因。本研究乃嘗試將tga及naaar基因黏接到水稻種子獨特之球蛋白