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Effects of concentrated ambient fine particles on plasma glycerophosphocholine in a myocardial rat model
No full text許多流行病學研究都已證實細懸浮微粒(PM2.5)會對心血管系統產生負面的健康效應，尤其對本身已罹患心血管疾病的病人會產生更嚴重的反應。大氣中懸浮微粒對心血管系統的致病機制有直接作用和間接作用兩個假說，其中心血管系統的損傷都與體內脂質的平衡擾亂有很大的相關性；磷脂醯膽鹼類，在磷脂質內佔最大比例的脂質，可能與懸浮微粒暴露誘導心血管系統異常有密切的關係。本研究比較心肌受損大鼠暴露到濃縮大氣懸浮微粒後血漿內脂質，尤其是磷脂醯膽鹼類的變異，希望能觀察到濃縮大氣懸浮微粒對易感受族群的分子層次影響。
雄性SD大鼠注射isoproterenol使其發展成為心肌受損大鼠後，會暴露65天濃縮大氣細懸浮微粒(平均濃度149 µg/m3)再進行犧牲，取大鼠血漿樣本，以Folch萃取法萃取脂溶性代謝物並使用核磁共振儀與質譜儀進行分析，得到的圖譜以多變相檢定法觀察暴露組與控制組血漿內脂溶性代謝物是否有差異。
統計結果顯示心肌受損大鼠暴露到濃縮大氣細懸浮微粒後，血漿內的脂質含量出現變動，核磁共振圖譜可發現暴露組的總脂肪酸鏈雙鍵數顯著下降，細懸浮微粒造成生物體內氧化壓力提升可能是雙鍵數下降的一個原因；質譜儀的資料則顯示單碳鏈的磷脂醯膽鹼類在暴露組會有一致的下降趨勢，可能是血小板凝結因子大量消耗，促使單碳鏈磷脂醯膽鹼類以特殊途徑生成血小板凝結因子而降低在血漿中的濃度；某些雙碳鏈的磷脂醯膽鹼類則會提高在血漿中的濃度。找出這些在血漿內出現變動的脂質與磷脂醯膽鹼類，可以提供後續研究一些線索與方向並縮小分析範圍，針對這幾個物質進行更進一步的研究，以解釋濃縮大氣細懸浮微粒的可能致病機制並發掘可能的生物標誌以做為前期預防的指標。Many epidemiologic studies have demonstrated that fine particles (PM2.5) will produce cardiovascular adverse effects, especially for those who already have cardiovascular disease. There have been two hypotheses about the mechanisms of ambient particulate in cardiovascular system. The first one is through direct effect. PM or its’ soluble materials activate the neural reflexes and disarray the heart rate rhythm, which sequentially conducting the cardiac arrhythmias. The other one is the indirect effect, which caused by increased oxidative stress and inflammation, then inducing the thrombosis and the atherosclerosis. Either direct effects or indirect effects will disturb the lipids’ balance during the course of cardiovascular disease. Glycerophosphocholine (PC), which accounted the most ratios in phospholipids, are likely to be affected by PM2.5 exposure and cause cardiovascular abnormal. In our study, we compare the differences of PC in myocardial rat plasma between PM2.5 exposure and control group. We intend to examine the molecular events of concentrated ambient particles in plasma of susceptible population.
Male SD rats were exposed to PM2.5 for 65 days after they became myocardial damaging rats by isoproterenol(150 mg/kg). After animals were scarified, plasma samples were taken and snap frozen. The samples were extracted by Folch’s extraction method and the hydrophobic layer was removed for farther analysis. Both NMR and MS were used to analyze the hydrophobic metabolite extracts of the rat plasma. The data from NMR and MS were pretreated for multivariate analysis to examine the hydrophobic metabolic variation among samples.
The statistic results demonstrated lipid fluctuations in rat plasma after PM2.5 exposure. NMR data showed that fatty acyl chain -CH2CH= and =CHCH2CH= decreased in exposure group. The raised oxidative stress after PM2.5 exposure may explain the decline of unstaurated fatty acyl chain. MS data indicated that the concentrations of lysoPCs were declined in exposure group. Moreover, numerous diacyl-phosphatidylcholine and alkyl-acyl-phosphatidylcholine were increased in the plasma of PM2.5 exposed rats.
Understanding the fluctuations of PC in plasma can help us to elucidate the possible mechanism of PM2.5 toxicity and to mine the possible biomarkers for cardiovascular disease progress
Karlodinium veneficum feeding responses and effects on larvae of the eastern oyster Crassostrea virginica under variable nitrogen:phosphorus stoichiometry
No full textMixotrophic feeding can be promoted by nutrient-enriched prey, a nutritional strategy which can provide benefits to some toxic microalgae under nutrient-imbalanced conditions. However, it is unclear how the nutritional condition of the predator or the prey affects the mixotrophy and toxicity of toxin-producing mixotrophs. Laboratory experiments were conducted to measure growth and feeding rates of Karlodinium veneficum with addition of Rhodomonas salina as prey under varied nitrogen (N):phosphorus (P) stoichiometry (molar N:P of 4, 16 and 32) of both predator and prey and with K. veneficum initially in different growth phases (exponential and stationary). Growth rates of initially exponential- and stationary-phase K. veneficum were enhanced in the presence of prey with reciprocal nutrient conditions. Feeding rates (measured as prey death rates) were highest for low-NP K. veneficum initially growing exponentially and mixed with N-rich prey. Maximum feeding rates of low-NP K. veneficum on N-rich prey during exponential growth were ~4-fold higher than the rates of high-NP K. veneficum on N-rich prey. The nutritionally different K. veneficum were tested with larvae of the eastern oyster Crassostrea virginica to compare putative toxicity. Larval mortality was significantly increased in 2 d exposures to high-NP K. veneficum monocultures in both growth phases. When mixed with N-rich prey, the presence of K. veneficum resulted in significantly enhanced larval mortality, but this was not the case for low-NP K. veneficum in exponential phase. Enhanced growth of K. veneficum and increased negative effects of K. veneficum on larval survival appeared to be highest when fed prey with higher N:P content
Seasonal succession of phytoplankton pigment and its composition in Fei-Tsui reservoir
No full text本研究以高壓液相層析技術(HPLC)，分析翡翠水庫水體中浮游植物的色素組成，以暸解浮游植物群聚結構之季節性變化，並且探討其可能的控制機制。在為期15個月(2007年10月至2008年12月)的週採樣調查中，浮游植物總生物量(以葉綠素表示)表層(20 m以淺)積分平均值介於0.51~5.55 mg Chl m-3，呈現秋季較高的趨勢。整體而言，隱藻、藍綠藻以及矽藻為三個主要優勢種類，分別貢獻25%、24%及20%的葉綠素濃度。此外，綠藻門生物(包括綠藻及青綠藻)佔12%的貢獻量，渦鞭毛藻則佔10%。藍綠藻雖在冬季光照較低時，數量略低，但整體而言，全年皆有穩定的生物量且季節性變化不明顯。相關分析發現，綠藻、青綠藻及隱藻與混和層深度呈正相關。冷季以隱藻及綠藻門生物為優勢種類，反映其適應低溫、低光照和高營養鹽的生態特性。在暖季時，以喜好高溫、高光照，適應低營養鹽環境的渦鞭毛藻為優勢種類。矽藻除在混合層由淺變深的轉換時期外(07年和08年11月)，皆為優勢種類，其生物量的時序變化與環境因子之間無顯著關係。進一步分析發現矽藻與渦鞭毛藻生物量的高值，在暖季時交替出現，且矽藻傾向分佈於較深之水層，而渦鞭毛藻主要出現於高溫、高光照，低營養鹽之表層區域。添加操控實驗，顯示在中光照控制組中，渦鞭毛藻的生長速率為矽藻的3倍；若在高光照及添加磷酸鹽的條件下，渦鞭毛藻生長速率則是矽藻的8倍。推論渦鞭毛藻與矽藻的消長情形及空間區隔現象，應是在高溫高光的環境下，渦鞭毛藻對營養鹽的競爭能力優於矽藻的緣故。此外，本研究所得之玉米黃素(Zeaxanthin ; 藍綠藻之指紋色素)濃度與流式細胞儀計數的藍綠細菌豐度呈顯著的線性關係，其斜率為1.06 ± 0.04 fg zeaxanthin cell-1 (r2 = 0.68, p<0.01, n = 361)，可作為本研究系統中估算藍綠藻豐度之轉換公式。To understand the annual variation of phytoplankton pigment and community composition as well as the relative importance of different phyla in oligotrophic freshwater ecosystem, pigment analysis via HPLC method was conducted on a weekly basis in the Fei-Tsui reservoir from Oct 2007 to Dec 2008. Epilimnion (20 m deep) integrated averaged chlorophyll-a concentrations (IChl) ranged 0.51~5.55 mg Chl m-3 with a bloom occurring in autumn. Overall, crytophytes, cyanobateria and diatoms were the three most dominant phyla accounting for 25, 24 and 20% of total IChl, respectively. Green algae (chlorophytes and prasinophytes, 12%) and dinoflagellates (10%) ranked the 4th and 5th in term of relative contribution. The analysis between phyla and environmental factors including temperature, light and mixed layer depth (a proxy of nutrient supply) was performed to understand potential controlling mechanisms. Cyanobacteria biomass did not change much during the studied period. Cryptophytes, prasinophytes and chlorophytes prevailed in the cold, low light level and high nutrient supply seasons. On the other hand, dinoflagellates could be categorized as warm water and low nutrient required species. Diatom biomass showed no significant relationships with environmental factors. It is notable that depletion of diatom bloom in turn was replaced by growing dinoflagellates in warm season. Furthermore, dinoflagellates occupied the light-rich surface waters in comparison with diatoms of similar size. Manipulation experiments suggested that plentiful nutrient stimulated the growth of dinoflagellate more than that of diatoms in high light level and phosphorus-enrichment conditions. Additionally, we found that zeaxanthin pigment concentrations showed a good correlation with cyanobacteria abundance with a slope of 1.06 ± 0.04 fg cell-1, which can be used empirically in converting diagnostic pigment concentrations to cyanobacteria abundance in the study area.口試委員會審定書i辭 ii文摘要 iii文摘要 iv錄 vi目錄 viii目錄 ix言 1.1 浮游植物族群的重要性 1.2 浮游植物的色素及其在分類及生態學上之應用 2.3 研究系統─翡翠水庫─背景簡介 3.4 研究目的 4料與方法 5.1 研究區域 5.2 色素分析與CHEMTAX軟體 5.2.1 色素標準品 6.2.2 CHEMTAX化學分類軟體 7.3 基本物理參數 8.4 其他生物化參數 8.4.1 磷酸鹽濃度及葉綠素濃度 8.4.2 流式細胞儀藍綠藻及浮游動物豐度計數 9.5 操控實驗 9.6 數據統計分析 9果 11.1 色素層析法之數據分析與驗證 11.2 基本物理化學參數 11.3 色素濃度之時空分佈 12.4 浮游植物生物量之時空分佈及其對總生物量之貢獻 13.4.1 各藻門生物量之垂直分佈 13.4.2 各藻門生物量之季節分佈 14.4.3 各藻門生物量對總植浮生物量之貢獻百分比 15.5 生物量之控制機制分析 16.5.1物理、化學機制 16.5.2攝食關係分析 17.6 操控實驗 17論 19.1 浮游植物種類季節消長情形 19.2 矽藻與渦鞭毛藻之消長關係 21.3 捕食壓力對浮游植物種類的影響 23論 25考文獻 26錄A、高壓液相層析沖提方程式 50錄B、色素標準品分析滯留時間及檢量線公式 50錄C、輸入之指紋色素比例表 51錄D、浮游植物之細胞數目相對百分比豐富度 51錄E、稀釋實驗所得浮游動物攝食速率結果 5
A Novel Six-DOF Electromagnetic Precision Positioner Utilizing Hybrid Magnetic and Fluid Mechanism
No full textA Novel High Precision Electromagnetic Flexure-Suspended Positioning Stage with an Eddy Current Damper
No full textDesign and Control of Novel Six-DOF Electromagnetic Precision Positioner Utilizing Hybrid Mechanism
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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