氧化壓力影響基因轉換表現對脂肪分化之作用
細胞脂肪分化是造成肥胖、骨質疏鬆、和糖尿病的重要前置因素。我們若要維持良好身材又想省去減肥藥的問題，那麼我們必須了解造成脂肪化的原因，才可能擁有好的預防之道。利用人類骨髓間質細胞可以分化成骨質與脂肪等細胞的特性，我們研究氧化壓力對間質細胞\r Ras基因轉換表現後骨質與脂肪分化的影響。結果發現以添加超氧根 (O2-，l5nM)形成氧化壓力，可促進正常Ras基因表現的間質細胞朝骨質分化;相反地，超氧根會促進\r Ras基因突變而不表現的細胞，朝向脂肪分化的現象。進一步研究其作可原理，發現氧化壓力可促進 RaS蛋白質啟動細胞外訊息活化酵素(ERK)，接著驅動骨質轉錄因子(CBFA1)表現，再到骨鈣蛋白質與骨結節形成。而抗氧化酵素(超氧根轉化酵素;SOD,5OOU/ml)的作用，可以抑制正常Ras基因細胞氧化壓力下骨質分化的進行;但不能防止氧化壓力促進Ras基因突變細胞，朝向脂肪分化的作用。總結而言:Ras基因的表現與否，是決定脂肪分化的關鍵切換點;也是影響氧化壓力對間質細胞朝骨質分化的樞紐。這種基因與氧化壓力互動影響骨質與脂肪分化的剖析，將有助於提醒人們:使用抗氧化劑來調節抗衰老、肥胖、和美容時，必須是在不同情況和不同基因體質的人，有所不同。
\r Human\r mesenchymal stem cells are able to differentiate into bone, muscle, cartilage or\r fat tissues. Our preliminary study with human mesenchymal cell line (HS-5) showed\r that HS-5 cells could differentiate to bone, cartilage and muscle but not fat cells\r as determined by histochemical staining of phenotypes. We have further studied the\r influence of oxidative stress on the switch between bone and fat cell differentiation.\r Results showed that oxidative stress started with exogenous superoxide, produced\r by the interaction of xanthine oxidase and hypoxanthine, promoted the differentiation\r of osteogenic lineage showing expression of osteocalcin and bone nodule formations.\r The mechanism was investigated and superoxide was found to induce ERK (extracellular\r regulated signal kinase) activation; and then the expression of osteogenic specific\r transcriptional factor (CBFA1). A plasmid containing ras-mutant (Ser 17 Asn) which\r can inactivate the expression of ERK was transfected into the HS-5 cells for studying\r the influence of oxidative stress on ras-mutated mesenchymal cells. Surprisingly,\r it was found that oxidative stress did not promote osteogenesis but it enhanced\r adipogenesis from the ras-mutated HS-5 cells. Further studies indicated that superoxide\r neither induced ERK activation nor CBFA1 expression, but it did enhance expression\r of adipogenic specific transcriptional factor (C/EBPα) and lipoprotein lipase in\r the ras-mutated mesenchvmal cells. Taken together, the study model to induce the\r bone cell differentiation from human mesenchymal stem cells may be employed to make\r bone cells for tissue engineering.
耍「薛骰」-Sicherman Dice 的探討
George Sicherman discovered that it is possible to take a couple of 6-sided dice re-labeling them with different positive integers (1,2,2,3,3,4) and (1,3,4,5,6,8) having the same probability distribution as rolling a standard pair of 6-sided dice. Such unique pair of dice is calling Sicherman dice. The secret behind the Sicherman dice can be studied by combining the powerful mathematical tool “Generating functions” with the symbolic manipulation software “Derive 6”, The same procedure may be applied to studying the possibility of the generalized Sicherman dice along the consideration of :\r (1) Adding more dice. (2) Changing the number of faces. To this end, we introduce the concept of the Sicherman Bound. For a given integer n, the number of n-sided Sicherman dice is finite. We computed manually such numbers for n?50 based on the method of “Elimination of negative terms”. Sicherman Dice 就是一對點數配置與正常骰子(6 面正立方體，點數為1到6)不同的骰子，它所拋擲出的每一種不同點數和(2,3,4...,12) 的機率恰好與一對正常的骰子相同。這種骰子是美國的Col. George Sicherman 所發現的。 Sicherman 更進一步指出：在不使用Sicherman Dice 的情形下，不可能找到一組大於或等於三顆的非正常骰子，它們拋擲出的每一種不同點數和的機率恰好與一組同數量的正常骰子相同。本研究的目標在於1. 尋求計算「Sicherman Dice 的組合和正常的骰子有相同的出現機率」的方法2. 證明Sicherman 結論的真偽及是否適用於其他正多面體(4 面/ 8 面/12 面/ 20面) 的標準骰子3. 修正Sicherman 的結論，並定義Sicherman 極限(Sicherman Limit)。在假設n面正多面體(n 為自然數， n ? 50 )存在的情形下，探討每一個正多面體的Sicherman 極限4. Sicherman Dice (Crazy Dice) 的延伸探討(1) 不同面數骰子的組合，是否可以找到面數組合相同，但點數配置不同的Crazy Dice( 如4 面與6 面的標準骰子組合，找到4 面與6 面的Crazy Dice)(2) 多個面數相同或不同骰子的組合，是否可以找到面數、個數及點數配置皆不同的Crazy Dice ( 如3 個4 面標準骰子組合， 找到2 個8 面的Crazy Dice)在研究的過程中，我發現以下的現象：(1) Sicherman Dice 的產生，是生成函數因式重新組合的結果(2) Sicherman Dice 是否存在，則視上述重新組合的結果是否有負項產生由於上述的觀察，我使用自行發展的「負項消去」法來檢驗Sicherman 結論的正確性及求得n 面正多面體其對應的Sicherman 極限。同時我也和Col. George Sicherman 取得聯繫， 討論當年他發現Sicherman Dice 的經過及其結論的限制條件，作為本研究未來發展的參考。
影像的色偏校正
The human eyes can adjust automatically the color of object under different illuminants. But digital camera does not have such mechanism, must join the white balance to simulate the color constancy of human eyes. There are many existing white balance methods. They can be categorized into two types. The first type utilizes the widespread assumption on the dealing natural scenery, which has the advantage of simplicity. Another type explores knowledge of the semantic content, which has the advantage of accuracy. In this study we modify and enhance the widespread assumption methods that can adopt the advantage of the simplicity and accuracy. Our proposed method is structured in two main parts: a color cast detector and a color cast remover. The detector first analyzes the color distribution of the image with simple statistical tools to determine whether or not the image has color cast. The remover, a modified and enhanced version of the widespread assumption methods ( gray world and max RGB ), is then applied on the color cast image. From the experiment results, it demonstrates the efficacy and performance of the proposed method.人類的視覺能夠自動修正因光線變化而改變的物體顏色，但是數位取像設備的感光元件卻不具有這樣的功能，必須加入白平衡的功能，才可模擬人眼維持色彩恆常的特性。現有的白平衡演算法可分為兩大類型，第一類型為廣泛假設型，具有運算速度快、與取像設備無關的特性，但是平均誤差會較大；另一類型為預知特性型，其特徵為準確性較高，但是運算較速度較慢、建立色彩特性資訊時所需的成本較高，本篇研究針對廣泛假設型的演算法做些修正與增強，使其具有較小的平均誤差以獲得較佳色彩品質的影像。我們將影像的色偏校正分為色偏偵測與色偏移除等兩個階段來進行，由於僅有被偵測出有色偏的影像才需要進行色偏的移除，所以可以避開將無色偏或固有色偏的影像做錯誤的修正，由實驗的結果看來，我們的方法確實有效，除了具有運算速度快、與取像設備無關的優點外，其色偏校正能力也較現有的方法好，使得影像色彩更能與人眼所見相近。
塑膠海岸－臺灣東北海岸微小塑膠污染之研究
一、目的：1.找出基隆沿岸是否受到塑膠微小物的污染，建立塑膠成分的簡易檢定法，3.分辨所發現塑膠微小物成分，4.試圖分析其污染源，並尋求減輕汙染方法。二、結果：本研究為首篇證實東北部海岸已遭受塑膠微小物污染之本土研究。我們想出了不用昂貴儀器的位之塑膠簡易成分判別法，發現海面漂浮的油渣含有塑膠微小物，還觀察到海岸生物（藤壺）由本來附生在岸邊的石頭上轉而附著於漂浮的塑膠垃圾及漁民和釣客所使用的浮標、漁網、浮桶等。三、為減少海岸的塑膠微小物污染，建議政府立法規定業者主義塑膠原料運送中產生的問題，並提倡垃圾分類，人民本身也應自我覺醒。Taiwan is an island, and the sea is very important for us. So in this study, we tried (1) to examine the small plastics (resin pellets and plastic fragments) pollution of the northeast coast, (2) to identify the components of unknown plastics by burning, soluability in organic solvents and relative weight but without using expensive instruments, and (3) to classify the small plastics we found and to find out where were they from. Our study is the first grassroot research proving that the northeast coast of Taiwan has been polluted by small plastics. We attempt to identify the components of unknown plastics without using expensive instruments. The present study discovers that there are many small plastics in the floating oil scum. The relation between the oil scum and small plastics needs more study. We finds marine life (bamacles) growing on floating small plastics. The ecological importance of this discovery needs more study. We also make suggestions for reducing the minute plastic pollution of the coasts: (1) the government should ask big companies to be more careful on the transport of plastic pellets, (2) people should be aware of the problems caused by small plastics.
台灣和東亞地區的氣候變遷
由人類活動造成的溫室效應可能導致地球溫度升高,聖嬰現象加劇等現象與災害,本文利用個氣候中心發展出的模式,推估台灣和東亞地區未來氣候變遷的情況,我們發現當大氣中的二氧化碳濃度增加為現在的1.9倍時,台灣地區的年平均溫度將升高0.85-2.50度C而東亞地區將會升高1.46-4.07度C,在同條件下個模式的平均推估量也顯示,台灣地區將每天增加0.10公厘的降水，而東亞地區每天將增加0.08公哩,我們希望這個研究結果可以做為其他相關研究的基礎,使大家提早因應未來氣候變遷所可能引發的種種變化;Greenhouse effect, incurred mainly by human activities may result in lots of phenomenon and damages such as the increasing of the world's average temperature and he aggravation f the "ElNino" effect. In this research, we simulate future metrological values by employing several simulation modes developed by different climate centers and predict future climate changes in Taiwan and East Asia area. We found that when the concentration of carbon dioxide exceeds 1.9 times than current value, the estimated range of the increased year-average temperature are0.85-2.5℃ and 1.46-4.07℃ for Taiwan and East Asia, respectively. Under the same condition, the ensemble mean reveals that the precipitation raises will be 0.1 and 0.08mm per day, for Taiwan and East Asia respectively. We hope our work can be the foundation of other related researches, and all the researches together can help for coping with possible damages caused by future climate changes.
嗜甲烷菌對丙烯催化模式之比較-溶解型與微粒體型甲烷單氧化酵素
在嗜甲烷菌中，甲烷與甲醇間的轉化是由甲烷單氧化酵素來進行。目前已知有兩種型態\r 的甲烷單氧化酵素，一種是溶解型甲烷單氧化酵素，存在於較低銅離子濃度之水溶液環境中﹔\r 另外一種為微粒體甲烷單氧化酵素，鑲嵌在細胞內質膜上，表現於較高的銅離子濃度環境下。\r 除了本身的天然基質－甲烷之外，其他種類之簡單烷烯類化合物，甚至芳香族化合物，均可\r 作為此酵素催化的基質。其中，甲烷單氧化酵素將丙烯轉化成環氧丙烯與甲烷轉化成甲醇的\r 催化活性非常接近，因此丙烯普遍被用來作為酵素活性測量的基質。為了直接測量它們的活\r 性，我們設計出一種方法，可以讓我們直接利用氣相色層分析儀，來偵測細胞的催化反應過\r 程。基於異丁烷在甲烷單氧化酵素幾乎不存在任何活性，故我們將其作為內標準氣體，並藉\r 由丙烯在氣相色層分析儀中吸收訊號的遞減來偵測細胞的催化活性。在多樣性的動力學實驗\r 中，我們發現以sMMO 為催化酵素時，丙烯的轉化是依據一級動力學反應趨勢而減少。相對\r 的，以pMMO 為催化酵素時，丙烯的減少趨勢則是依據零級動力學反應模式進行。在比較完\r Pipes 緩衝液、上清液蛋白質及內質膜蛋白質溶液之丙烯吸附量測試結果後，我們發現內質膜\r 蛋白可吸附的丙烯分子相對於其它兩種溶液是最多的。依據Michaelis-Menten 動力學理論，\r 可得到以下結論﹕丙烯的轉化在sMMO 中是以基質受限的催化形式進行，而在pMMO 中則\r 已達到最佳的催化速率。\r \r In methanotrophs, the oxidation of methane to methanol is catalyzed by methane\r monooxygenase. There are two distinct forms of the enzyme associated with different gene\r products. One is the soluble methane monooxygenase (sMMO) expressed in the cytosolic portion\r of the cell and grown under copper-limiting growth conditions. The other enzyme is the\r particulate methane monooxygenase (pMMO), a membrane-associated protein that is expressed\r under high copper-to-biomass ratios. In addition to the natural substrates of methane gas,\r simple aliphatic alkanes, alkenes, or even aromatic compounds could be used as the substrates of\r the methane monooxygenase. In those gaseous simple alkenes and alkanes, propylene converted\r to propylene oxide by methane monooxygenase has been considered as popularly use for enzymatic\r activity determination because of its comparable activity to the methane gas. To measure the\r catalytic behavior of the methanotroph directly, we design a method to choose isobutane as the\r internal standard because of the negligible activity in the methane monooxygenase. The catalytic\r activity can be simply inferred from the decrease of the gaseous propylene signals in the GC\r chromatograms by generating the liquefied epoxides mediated by MMO within the methanotrophic\r bacteria. Under various kinetics measurements, when we incubate the methanotroph grown under\r copper-limiting concentrations, we observed the diminishment of propylene follow a first-order\r kinetic behavior with the over-expression of soluble methane monooxygenase. However, the\r growth of bacteria under 40 M presents the zero-order kinetic trend with the bulk expression of\r pMMO. After the quantification of the dissolved propylene in the deionized water, soluble\r proteins solution as well as membrane proteins solution, we observe the membrane proteins could\r adsorb more propylene molecules in comparison with the other solution mixtures. By considering\r Michaelis-Menten kinetics, we conclude the propylene conversion in sMMO is under substrate\r limiting catalysis whereas the pMMO has attended the optimized velocity of propylene conversion.
遞迥數列及渾沌現象
給定一個P∈(0,1),令k0=0, p0=p，定義k1為能使 的最小正整數k，而 ; 相同的，對於給定的kn-1, kn 為能使的最小正整數k, 。若存在kn 使得，則稱p∈ In; 若對於所有n 與kn ，，則稱p∈ I∞。如此區間(0,1)可分解成集合I1,I2,…,I∞。
榕樹粗萃取液對種子萌發及生長之影響
相剋作用是指植物在代謝過程中釋放出有毒物質以抑制本身或鄰近植物種子萌發及植株發育生長的過程。一般認為，榕樹是具有相剋作用的常見植物，但很少見到相關的文獻探討。本實驗利用榕樹不同組織萃取液，以小白菜、結球白菜與阿拉伯芥作材料，探討該萃取液對上述植物發芽與生長之影響，結果顯示榕樹葉萃取液所造成之影響較顯著，不同榕樹組織的萃取液、不同濃度的萃取液對不同植物所產生的效果不盡相同，針對不同生長期的植物進行處理所造成的影響亦有差異。進一步以管柱層析法與高壓液相層析法（HPLC）分離葉萃取液，結果發現以正己烷和乙酸乙酯75：25為沖提液的條件下，於HPLC的層析圖中分離時間約8分時所流出的物質具最明顯的抑制作用。電泳剖面分析顯示處理與未處理間有些許蛋白質條帶差異，此變化蛋白可能與植物幼苗對該萃取液之耐受性有關。利用核酸微陣列(microarray)對榕樹萃取液處理之阿拉伯芥植物進行基因表現分析，發現榕樹萃取液對植物部分基因表現也有促進和抑制的情形，經由基因體與蛋白質體分析法可推論出一些受影響之相關基因。 Allelopathy was defined as a phenomenon which certain plant species, by secreting metabolites to the environment, can suppress the growth of themselves, seed germination and/or growth of other plants in the same habitats. Banyan （Ficus microcarpa L.f.） is a plant species in our campus likely to have allelopathy effect. However, documents describing such action on allelopathy were rare. In this study, we applied the crude tissue extracts including leaves, stems, roots of banyan onto the germinating seeds of Pai-Tsai （Brassica rapa L.ssp.chinensis（Rupr.（Olsson）））, Chinese cabbage （Brassica pekinensis Rupr.） and Arabidopsis（Arabidopsis thaliana, ecotype Columbia-0） to study the effects of such plant extract on the germination and seedling growth of other plants. It is found that allelopathic effects on seed germination vary among different tissues used for extract preparation. Different concentration of the extract also yield various degree of allelophathic effects. It is also noted that the application of extract onto the post-germinated sprouts has less effects on plant growth. The extract of leaves was subsequently chromatographed over silica gel using hexane/EtOH gradient solvent system and HPLC. The result showed that there was one fraction about 8 min in the chromatography of HPLC eluted with 25% EtOAc in hexane had the most inhibitory effect. SDS-PAGE analysis on the electrophoretic profiles of water soluble proteins has explored a different band pattern between the treated and non-treated sprouts. The observed band difference might provide a clue for exploring proteins which reacted differently upon the application of extract. DNA microarray analysis on the effect of banyan extract on Arabidopsis gene expression has also been employed to characterize genes responsive to the allelophathic treatment. Cross-comparison between the differential transcript and protein profiles will reveal key regulators in plants experiencing allelophathic condition. \r