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本實驗的觀測乃著重於觀測各定點之臭氧濃度與該地天氣因子;如溫度、相對溼度、氣壓、雲量、風速、日照強度等與之比較並控制所有可能的變因,來推測一地空氣污染的程度,並從中思考影響一地臭氧濃度變化的要素。 利用自製的熊本試紙來測量在對流層中臭氧的濃度,進而來推論出我們所設的測站附近的空氣污染程度。 由實驗了解臭氧濃度和其他天氣因子如溫度、相對溼度、風向、風速、日照強度、紫外線強度、工廠作息或交通流量等因素有著很微妙的關係。 最後,我們歸納出在做此實驗時所遇到的相關問題與解決方法。 This experimentation is about the ozone of troposphere. We try to find out how the weather elements affect the ozone consistency (for example: air temperature, relative humidity, air pressure, cloudage, wind speed, solar insolation), and to discover the relation between the ozone consistency and the air pollution. We use the test paper which is made by ourselves to measure the ozone consistency of troposphere, so that we con use the date to infer the air pollution level at the area where we conduct our tests. According to our experiment, we find out the ozone consistency and other weather elements (ex: air temperature, relative humidity, air pressure, cloudage, wind speed, solar insolation or traffic), have some delicate relations with each other. Finally, we conclude all the relative problems we face in this experiment and their solutions.
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Vitamin C in Cold and Flu Drinks
This chemistry project was designed to measure the vitamin C levels within liquid cold and flu remedies, and see if they had been accurately stated on the package. A range of Cold and flu drinks was selected, including one made with only cold water (Lemsip Original, Lemsip Max, Effer-C-Cold Water, Relief and Lemting) .The procedure used to carry out the experiment was a redox titration, each trial required two titrations, with the first being a blank titration to determine a sodium thiosulfate concentration in the absence of vitamin C. The following Drinks had more Vitamin C than stated on the packaging – Lemsip Original (19.4%), Lemsip Max (22.1%), Effer-C (17%) and Relief (8.8%). Lemting was the only drink made to directions that had less Vitamin C than stated by 31.8%. Two conclusions can be drawn from these results, the first being that Lemting has the most inaccurately recorded mass of vitamin C and is also the only drink with less vitamin C than stated. The other interesting result is that Effer-C (the only drink made with cold water) had 170mg of extra vitamin C. Of the other drinks that had more vitamin C, Lemsip Max was next with an extra 22.8mg. Early research had showed that Vitamin C was affected by high temperatures (above approximately 70oC) and, as cold and flu drinks are commonly made with hot water the Vitamin C levels might change when they were made up. This poses a further possible research question which is, in making cold and flu remedies with hot water is some of the available Vitamin C being destroyed?
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In our daily life, objects and the contacts between objects they will have mutually affect each other, some initially chaotic systems after a sufficient amount of time will mutually correct each other, and finally achieve synchronization (example: the speed of bird and fish migration, market prices, infantry…), although some are unable to achieve this. We will illustrate and explain the synchronization system, its process and discover the conditions for synchronization. Using linking concepts, we will integrate the coupled map lattices with global coupling and coupled map lattices with intermediate-range models into a synchronization mode in order to simulate a synchronization system. We first used a small system of n≦50 to obtain results that will demonstrate the linking concepts: 1. The more chaotic a system, a longer period of time is required for synchronization. 2. An increase in the number of individual objects requires an increase in the range of concepts and the amount of time in order to achieve an in depth synchronization. 3. Initial concept values which randomly effect synchronization critical point conditions are not obvious in a mathematically incorrect graph. In a closer look, when we increased the synchronization to n≦400 and the number of times to t-->100,000 we discovered:1. Using the function G(x) we hoped the results from the graph after apply the function and correction able to overlap and test with “Scaling and Universality in Transition to Synchronous Chaos with Local-Global Interactions”, but the part which overlapped the measurements was not identical: 2. We can use the significance of the critical point and the Interactive Process to find the approximate value of the critical value up to 4 digits following the decimal point. 3. We can also use the approximate value to find out the range for the simultaneous conditions and the various points on the system itself, as well as obtain a negative correlation between them, and then it can be similarly expressed with using a curve. A computer can calculate values with this kind of enumerating method, even without any special resolution capabilities to quickly obtain large amounts of approximate values of simultaneous conditions, this is especially true when calculating unfamiliar systems. 日常生活中,物件與物件的接觸,彼此會互相影響,有些原本雜亂的系統再經過充裕時間的互相修正後,最後竟能達成同步(例如:鳥群、魚群遷徙的速度、市場價格、行軍步伐…),有些則不能。因此,我們試著利用描述同步系統的模型,觀察系統同步的過程,並且找出同步的條件。由連結的觀點,我們將Coupled map lattices with global coupling 和Coupled map lattices with intermediate-range 模型的優點整合成Synchronization mode 去模擬同步系統。我們先用小系統(n≦50)得到能印證連結觀點的結果:(一)、系統越雜亂,就需要稍長的時間同步;(二)、個體數越多時,各點需要更大範圍的點數去影響於每單位時間內以及更深的影響才能同步;(三)、起始值隨機影響同步臨界條件並不明顯,在誤差範圍內。更進一步,我們將系統推向n≦400 點,t→100,000 次,我們發現:(一)、在”G(x)”我們希望能將圖形經過函數修正之後能疊和,驗證”Scaling and Universality In Transition to Synchronous Chaos with Local-Global Interactions ”中的結果,但只有部分疊和,尺度不相同;(二)、可以直接利用臨界點的意義用十分逼近法求出臨界值的近似值到小數後四位;(三)、我們用近似值也能發現同步條件與系統各點本身可跳躍的數值範圍是負相關,可用曲線去近似。這種窮舉方式,交由電腦運算,不需要特別的解析能力就能夠快速且大量求得同步條件的近似值,尤其在運算不熟悉的系統時。
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Eye gone V.S.eyeless決定果蠅複眼發育基因之協同作用與未知調控基因之尋覓
In this study, we try to know how ectopic eye genes: eyeless(ey), eye gone(eyg), twin of eyeless(toy), twin of eye gone(toe) act cooperatively, and look for some unknown genes which affect the function of eyg. First, through human trans gene screening, we find two human genes change the phenotype of ey>eyg into dorsal out-growth when they co-express with eyg (ey>eyg+X). It means the two genes may relate to cell proliferation. Second, by sequencing the insert genes of mutant fly which was found by EP screening, the result shows the site of the insertion is the same as effete (eff) gene. eff translated wrong proteins which differ from functional ubiquitin-conjugating enzyme may be the major cause of the mutant eye . 本研究係探討果蠅複眼異位基因eyeless(ey)、eye gone(eyg)、twin of eyeless(toy)、 twin of eye gone(toe)間的協同作用,並尋找與eyg 有交互作用的基因、突變株。藉由人類基因轉殖篩選,找到兩株人類基因轉殖株,當其與eyg 共同表現時(ey>eyg+X),會改變ey>eyg 的複眼性狀,造成dorsal out-growth,顯示這兩個基因可能與細胞增生有關,此外,藉由EP screening 複眼發生突變的果蠅之UAS 下游基因經比對後,位置與effete(eff)部分契合,推測複眼發生突變的原因是eff 的功能發生異常,致使細胞內蛋白質代謝失常所致。
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The Titanium Dioxide Toilet Disinfectant
This project aims to improve the quality of toilet hygiene. The product designed should fulfill the requirements of being an environmentally friendly, user friendly and economical toilet seat system which guarantees the safety and hygiene of the toilet. This project also aims to discover the efficiency of the toilet seat system in eliminating pathogens through conducting various experiments.\r In this project, the photocatalytic property of titanium dioxide is applied. When titanium dioxide is under exposure to ultraviolet radiation, they generate free radicals, which are efficient oxidizers of organic substances. Also, research has shown that the safest ultraviolet light used will be UVA. Thus, by using titanium dioxide paint under exposure to ultraviolet light to oxidize pathogens and toxins, the aims will be achieved. Other than that, experiments will be conducted to explore the efficiency of titanium dioxide under exposure to UV radiation in eliminating pathogens by counting the number of bacteria on the toilet seat system after different time intervals the seat system has been turned on.\r The procedure of constructing the product includes drafting the product, purchasing the appropriate apparatus and materials, constructing the prototype, and checking if the product fits the goals set. Lastly, improving the design based on the flaws found during the checking procedure, as well as checking the product to see if it fits the original goals set.\r The procedure of the experiments aimed to explore the efficiency of titanium dioxide under exposure to UV radiation in eliminating pathogens conducted includes\r counting the number of bacteria on the toilet seat system after different time intervals by inoculation of bacteria on the agar plates.\r Test results showed that the number of bacteria had a steady and notable decline after different time intervals. Results also showed that bacteria would be thoroughly terminated after the system had been turned on for at most one hour. The information was then used to set the delay timer to restrict the amount of time the ultraviolet lamp was turned on to save energy.\r Moreover, the toilet seat system has also been improved so that it will complete the automatic cleaning procedure even without the user lowering the toilet seat. This improvement was made so that the product could be more convenient to toilet users.\r The system also deodorizes the toilet as the oxidization of bacteria and organic substances reduces the putrid odor released by them when they carry out chemical reactions.\r In conclusion, the project succeeds in accomplishing the goals set and is capable of improving the quality of toilet hygiene, especially in common households. The project is also successful in finding out that the toilet seat system is efficient in eliminating pathogens.
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單細胞浮游藻類對紫外線防禦機制之探討
在先備知識中,我們知道在缺少營養鹽及紫外線傷害下,浮游藻類的葉綠體會因為過氧化物(R.O.S.)的增加而受到破壞,進而影響光合作用的進行,甚至導致死亡。所以確實了解常見浮游藻類生理狀態和環境的影響,以期待未來可利用大幅度提高浮游藻類生產力的方式有效降低溫室效應的影響為本實驗的主要目的。故實驗設計針對兩種常見的海洋種浮游藻類(Tetra、Ske),在不同紫外線光譜(UVAB、UVC)的照射下,觀察R.O.S.的產生量和T-T dimer的表現狀況,並對照兩者之間的關係。結果我們發現:綠藻(Tetra)和矽藻(Ske)在UVAB、UVC 的照射下皆會產生R.O.S.,且綠藻產生的量較少;但在UVC 照射下皆有DNA 損傷(產生T-T dimer)。故推估並不是綠藻(Tetra)擁有紫外線的特殊防禦機制,而是能較有效地代謝R.O.S.。As we know, under the condition of unorganized salt’s shortage and the harm of the ultraviolet ray, the phytoplankton’s chloroplast will be destroyed because of the increasing peroxide (R.O.S.). Furthermore, the ultraviolet ray will have an effect on the process of photosynthesis, and even result in the death of phytoplankton. So, we intend to promote the production of phytoplankton in order to lower the influence of greenhouse effect by probing into the environmental influence on the physiology of phytoplankton. The experimental is designed to observe two common marine phytoplankton: Tetra and Ske. By close observing Tetra and Ske exposed to different wavelength of ultraviolet way (UVAB and UVC ), we contrast the production of R.O.S. with the appearing of T-T dimer. We observe that both Tetra and Ske will produce R.O.S. after being exposed to UVAB and UVC , but Tetra produce less than Ske, and that UVC will do harm to both the DNA of Tetra and Ske (producing T-T dimer). Based on the result of the experiment we estimate that Tetra can catobolize R.O.S. efficiently instead of having a unique defensive mechanism against ultraviolet ray (UVAB and UVC under discussion in this experiment.)
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台北市內湖金面山區兩棲爬行動物資源調查之研究
本研究之目的主要為調查臺北市內湖金面山區附近兩棲、爬行動物之物種概況,建立內湖地區的兩棲爬行動物基本生態資料庫,期望藉此研究可推行高中科學教育研究的基礎,並可充實自然生態保育與愛護鄉土心靈教育的實際教材。 調查研究工作是由2003年4月開始,至2004年5月為止,十四個月期間,總計85次的夜間野外觀察,已確認記錄兩棲爬行動物的種類共計有37種(分屬2綱3目13科24屬),蛙類:4科13種,蜥蜴類:4科9種,蛇類:4科13種,龜鱉類1科2種。 各物種總出現隻次方面,蛙類以拉都希氏蛙的1547隻次為最多,最少的是長腳赤蛙及斯文豪氏赤蛙,僅6隻次。蜥蜴類以黃口攀蜥的1995隻次最多,最少的為麗紋石龍子,僅4隻次;蛇類及龜鱉類以龜殼花最多,共計85隻次,而以梭德氏游蛇、大頭蛇、白梅花蛇、赤背松柏根、南蛇、盲蛇、食蛇龜及材棺龜等均只有1隻次為最少。 出現頻度方面,十四個月份中,蛙類的拉都希氏蛙及古氏赤蛙皆有出現,在85次的調查期間,則是以拉都希氏蛙的97.65%為最高,最少的為長腳赤蛙,只有3.53%;蜥蜴類的黃口攀蜥於十四個月份皆有出現,而在85次的調查期間,則有75次、97.65%最高出現頻度,麗紋石龍子於14個月份及85次的調查,出現頻度均是最低,各是21.43%及3.53%;蛇類及龜鱉類物種中,以龜殼花14個月及61次的出現記錄為最高,出現頻度分別是100%及71.76%;而食蛇龜及材棺龜均只有出現一個月及一次,故其出現頻度為7.14%及1.18%。 分佈廣度而言,於二十二個調查樣區中,蛙類以拉都希氏蛙的95.45%為最大,最小的為長腳赤蛙及斯文豪氏赤蛙的18.18%;蜥蜴類以黃口攀蜥的100%為最大,,最小的是無疣蜥虎的9.09%;蛇類則以龜殼花的86.36%為最大;龜鱉類物種皆僅4.55%的分佈廣度。 各樣區出現物種數方面,蛙類以A區的11種為最多,蜥蜴類以二期校區的7種為最多,蛇類是以AB區的9種為多;各樣區中,則是以AB區所發現的兩棲爬行動物物種數最多,合計共有22種物種。 由研究結果得知,調查樣區內的兩棲爬行動物物種歧異度大,其中蛙類的優勢物種為:拉都希氏蛙,蜥蜴的優勢物種為:黃口攀蜥,而龜殼花則為蛇類的優勢物種。而環境溫度的變化,與調查樣區內兩棲爬行動物出現活動的總物種數有顯著之相關性。 ;The goal of this research paper is mainly to investigate Taipei city, Neihu District, nearby Jin-Mian mountain’s amphibious and reptiles for the establishment of the lake area amphibious and reptile basic ecology information bank. It is hoped that this research will provide a foundation to further promulgate the high school science education and research, and may enrich the natural ecology protection and education materials for the loving care of local environment. The investigation started from April, 2003 to May, 2004, or for 14 months period and amounted to 85 times of field observations at night. It was confirmed that there were 37 species of amphibious and reptile ( 2 classes 3 aria 13 families 24genus),amphibious species: 4 families 13 species, lizard: 4 families 9 species, snake: 4 families 13 species, turtle: 1 family 2 species. In regard to the number of times of appearances, amphibious species of Rana latouchii had the most appearances with 1,547 times, and the least appearances was the Rana longicrus and the Rana swinhoana with only 6 times; for the lizards, Japalura polygonata xanthostoma had the most appearances with 1,995 times, and the least appearances was Eumeces elegans with only 4 times; for the snake and turtle, Trimeresurus mucrosquamatus had the most appearances with 85 times; for the Amphiesma sauteri sauteri, Boiga kraepelini, Lycodon ruhstrati ruhstrati, Oligodon formosanus, Ptyas mucosus, Ramphotyphlops braminus , Cistoclemmys flavomarginatn and Mauremys mutica , each had appeared only 1 time. On the appearance frequency, within the 14 months, amphibious species Rana latouchii and Rana kuhlii, Rana latouchii appreared 97.65%, the highest within the 85 investigations period, and the least was the Rana longicrus with only 3.53%; lizard Japalura polygonata xanthostoma had appeared within these 14 months, but in 85 investigations period, their frequency was 75 times, or 97.65% at the highest frequency. Eumeces elegans there upon within the 14 months and 85 investigations, had the lowest frequency each at 21.43% and 3.53%; for the snake and the turtle species, Trimeresurus mucrosquamatus within the 14 months and 61 appearances had the highest frequency record at 100% and 71.76%; but Cistoclemmys flavomarginata and Mauremys mutica only appeared once in a month and, therefore its frequency was at 7.14% and 1.18%. For the distribution breadth, in 22 investigation sample areas, amphibious species take Rana latouchii of the amphibious kind had the biggest record at 95.45%, and the smallest was Rana longicrus and Rana swinhoana at 18.18%; for the lizards, Japalura polygonata xanthostoma was 100% as the biggest, and the smallest was Hemidactylus bowringii at 9.09%; for the snake, the Trimeresurus mucrosquamatus was at 86.36% as the biggest; the turtle species had only 4.55% distribution breadths. For the number of appearance in each area, amphibious species in area A had the most with 11 species, lizard of second period school area had the most with 7 species, the snake of area AB had the most with 9 species. In all other areas, the amphibious reptile species number in area AB had the most with 22 kind of species. From the results of the research, the biodiversity of amphibious and reptile species within the investigation areas is very high, Rana latouchi is the codominant of Frog; Japalura polygonata xanthostoma is the codominant of Lizard, and Trimeresurus mucrosquamatus is the codominant of Snake.
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在網際網路蓬勃發展的時代,電腦病毒也更加的猖獗。雖說防毒軟體百家爭鳴,但對於未知病毒的防治技術仍然束手無策。本研究的目的在追溯出電腦惡意程式運行模式,利用IDA靜態反編譯軟體與病毒原始碼尋找出病毒共同的特徵,阻斷其滋生途徑。 本研究在實驗中,研究者利用Borland C++ Builder 6作為應用程式開發環境,配合WinAPI函數與TRegistry類別設計出參數監控系統。研究顯示不論是修改於Window 9x架構下的win.ini, system.ini,或是Run與Run Service之下的資料項,本系統都能有效運作。此系統能成功的攔截到惡意程式對Registry鍵值的讀寫,亦即當使用者否決其修改鍵值時,惡意程式無法在重新開機後運行;易言之,惡意程式失去執行效力。 實驗結果發現,參數監控系統可攔截惡意程式之修改命令,防止未知病毒與惡意程式開機自動運行,以此達到未知病毒的攔截基礎技術。本研究之結果可補強市售防毒系統,對於未知病毒的攔截,能達到完整的防護效果。 Computer viruses become more rampant in the rapidly-developing era of Internet. With the various kinds of Anti-Virus software, people still can do nothing about detecting the unknown viruses. This research aims to trace back the computer virus function mode. By using IDA Pro Disassembler and Virus Source, we can find out the common characteristics of viruses. Thus, we can stop viruses from thriving. The experiment uses Borland C++ Builder 6 as the Registry Detection System by coordinating Win API and TRegistry. It works no matter by modifying win.ini and system.ini under the structure of Window 9x or by modifying Run Value and RunService Value. Moreover, it can intercept the viruses from reading and writing of the ValueKey. As the users deny the modified ValueKey, the viruses cannot run after resetting. In other words, the viruses lose their effects. The results present that Registry Detection System can intercept the modifying commands and prevent the automatic running from unknown viruses. By doing so, we can acquire the basic technology of intercepting the unknown viruses. The application of this study can improve the functions of Anti-Virus. In this way, through protection from unknown viruses can be obtained.
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My school requires year 13 students to complete a year long project of a topic of their choice, culminating in the presentation of a thesis, a display and speech to a public audience. Many different topics appealed, but in the end I decided to build a micro wind-turbine. I have always been fascinated with mechanics, mathematics, engineering, aerodynamics and electricity. A wind turbine is a mixture of these technologies, with the overall goal of electricity production. In a world that is starting to see the true costs of fossil fuels, renewable energy seems to be increasingly popular and the demand for electricity is always growing.\r I was aware that building a wind-turbine from the foundations up wouldn’t be easy. Many of the experts I contacted in the early days cautioned me against trying such a complex thing in one year, at the same time as completing a full Year 13 course. There were, however, people prepared to support me. Michael Lawley, who builds micro wind turbines in New Plymouth was very helpful, just full of priceless knowledge and gave me a few basic parts to start with. The knowledge gained from Doug Clark, who also builds his own 11 kW wind turbines, was such an inspiration. Later I had practical help from Wilson Springford and Darron Matthews.\r I investigated and documented the history of and current state of wind technology, as well as my own experience and learning in the design, construction and testing process. I thought it would be interesting to find out how the electrical and mechanical side works.\r The generator, a washing machine motor, needed to be completely rewired, and converted to DC (direct current) from AC (alternating current). I built my own 3-phase AC to DC converter.\r Other parts like the disc brakes and bearings had to be found. The rest was hand-made and every part, to a certain extent, had to be modified. Probably more than twenty braking system design attempts led to the final decision to incorporate the wind-activated hydraulic disc brake where the wind paddle starts to ease the brake on over a certain wind speed.\r I studied the dynamics of wind turbine blades, their shape, the material they were made from and how this affected their performance. The decision to make my own blades helped me gain a great sense of achievement and knowledge of blade design. I found some New Zealand made 100% recycled plastic pipe, an added bonus because I wanted to have minimal environmental impact. I designed the turbine with three blades to give better starting torque along with a lower top speed, perfect for how I wired the generator.\r I designed the swivel, the part of the wind turbine that enables the power cables to get from the turbine down the tower without twisting up and has the job of carrying the whole turbine, which is mostly made from recycled aluminium. The steel and bearings used to create the swivel were all second-hand parts and materials. The power from the turbine passes through the swivel into the cables and down the tower. The main mast of the tower is a little over 4.7 metres and pivots on two shorter supporting poles which go down around 2.6 metres to the bottom of the reinforced concrete foundation.\r I managed to, design and construct an operational prototype micro wind-turbine, incorporating recycled and recyclable materials as much as possible, with the end result surpassing all expectations.
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Biosolids : Bio-transfer Factors of Trace Metals
With an increase in the use of biosolids as a soil replacement and as a fertilizer for crop production, consumers continue to question the safety of crops grown in biosolids.Although past research has shown that there are no adverse affectsin the nutritional value of plants grown in biosolids, I furtherresearched the safety levels of trace metals in crops fertilized using biosolids.
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We investigate the machinery producing successive Simpson’s paradoxical reverse. Taking advantage of algebraic and geometric techniques, we obtain the following results. Take playing baseball for example. In our study, we find that Simpson’s paradox only occurs when the hitter’s hits over 3 times in one game. Set n equal to the times I will hit in one game. If my batting average in each game is at least(n ?1)/2 times higher than the others’; then I am sure that my total batting average would not be invert by the others. In order to find how many the lattice points in the triangle, we use Pick’s formula. But sometimes, the Pick’s formula is not appropriate to triangles whose vertex are not all lattice points. So we develop New Pick’s formula to estimate the number of lattice points in such kind of triangles. Besides, we also find an iterative algorithm to produce successive “Simpson reverse” phenomenon by using C++ language, and we can therefore produce as many “Simpson’s set of four sequences” terms as we like(not beyond the computers’ upper limit).Moreover, if both sequences of ratios converge, then they must have the same limit.我們探討了一般人乍看之下顯得頗弔詭的辛普森詭論。我們配合GSP 作圖,用解析幾何、設立直角座標系和C++ 程式的運算,找出在特殊情況下或一般情況下所產生的辛普森數列組和特殊的性質,並且以棒球場上的打擊率為例子來做印證。通常一場棒球賽中,每個人平均上場3 次~4 次,經過我們的討論,發現要發生逆轉的機會只有在上場達到4 次或以上時才會發生。?了求出在直角座標系中可以滿足的格子點個數,我們用了Pick公式,但?了更準確的估計,我們引進了虛點的概念,重新推導出了新Pick 公式。另外,我們還發現,假設兩個人上場比賽,若打了2 場,且每場最多上場打擊K 次,其中的一個人的打擊率只要是另一個人的(k-1)/2倍以上就保證不會被逆轉。我們又找到了連續產生辛普森逆轉的演算法,利用C++ 寫出程式,經由演算法和遞迴式,製造出項數可任意多(只要電腦能夠承受)的辛普森數列組,且我們發現若兩個比值數列接收斂,則極限趨近於同一個數值。
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突變ras基因造成過度表現在骨髓間質幹細胞啟動氧自由基誘導細胞凋亡
特定基因的表現與不同氧自由基的產生,已知會影響細胞的生長和死亡。我\r 個人有興趣利用間質幹細胞體外培養擴充,以為筋骨組織再生的可能應用。因此\r 利用轉植(transfect)突變ras 基因(Glu61Leu)進入骨髓間質細胞株(HS-5 cells),來\r 控制ras 基因表現的高低,進而研究這些間質細胞隨著Ras 蛋白質表現的高低,\r 對氧自由基引導細胞生長與死亡之影響。結果發現ras 基因高度表現的間質細胞\r 生長減緩;相較於原生株平均減少62.4%。進一步研究其生長減少是否與細胞凋\r 亡有關,發現ras 基因高度表現的間質細胞凋亡確實比原生株高22.6%。探究其\r 凋亡原因,發現與caspase-3 有關但和粒腺體功能無關:因為caspase-3 有活化,\r 但是以粒腺體膜電位螢光追蹤劑JC-1 測得的膜電位卻沒有改變。追蹤ras 基因高\r 度表現的間質細胞其細胞內氧自由基的產量,發現Ras 高度表現株其細胞內氧自\r 由基明顯增加。當細胞外加入超氧根轉化酵素(SOD, 500 U/ml)去清除超氧根時,\r 對Ras 高度表現細胞的凋亡沒有影響;但是外加觸化酵素(catalase, 500u/ml)於培\r 養液中,卻可以抑制ras 基因高度表現的間質細胞內caspase-3 活化和細胞凋亡;\r 並且增加細胞生長循環促進分子Cyclin D1 的表現。從這些研究我們歸結出兩點\r 重要新發現: 1) ras 基因突變造成Ras 高度表現時,會促成細胞內特定氧自由基產\r 生,使得細胞生長減緩並進行細胞凋亡,只有特定抗氧化酵素(catalase)才能恢復\r 其異常; 2) Ras 蛋白高度表現而引導氧自由基產生的細胞凋亡與caspase-3 活化\r 有關,但與粒腺體功能無關。根據這些發現,未來我們或許可以朝調節特定氧化\r 還原反應或使用caspase-3 抑制劑去調控間質幹細胞的生長,以供筋骨組織再生\r 的應用。Certain gene’s expression as well as different species of oxygen radicals can\r affect cell growth and apoptosis. We are interested in amplifying mesenchymal\r progenitor cells for the application of musculoskeletal tissue regeneration. Thus, we\r transfected a mutant ras gene (61Glu/Leu) to change Ras protein expression in the\r mesenchymal progenitor cell line (HS-5 cells) and studied how ras expressing levels\r influenced intracellular oxygen radicals, and its relationship to cell growth and\r apoptosis. Results showed that Ras over-expressing HS-5 cells grew slower than those\r with wild type ras HS-5 cells and revealed a higher apoptosis rate. The higher\r apoptosis in Ras over-expressing cells was not related to mitochondrial dysfunction\r since mitochondrial membrane potential was normal as determined by flow\r cytometric analysis of JC-1 fluorescent staining assay. The higher apoptosis was\r related to higher caspase-3 activation. Further studies showed that Ras\r over-expressing HS-5 cells revealed a higher production of intracellular oxygen\r radicals in comparison to those with wild type ras HS-5 cells. Addition of catalase\r (500 u/ml) but not superoxide dismutase (SOD; 500 u/ml) specifically revived the cell\r growth associated with increase of cyclin D1 expression, but decrease of apoptosis\r associated with lower caspase-3 activation. Results from these studies demonstrated\r two important findings: 1) the ras gene over-expressing in a ras-mutant HS-5 cell line\r triggers a higher production of intracellular oxygen radicals resulting in higher cell\r apoptosis; and 2) the higher oxygen radicals related cell apoptosis is mediated by\r caspase-3 but not mitochondrial dysfunction. Based on these findings, we may\r propose to regulate mesenchymal progenitor cell growth for musculoskeletal tissue\r regeneration via modulation of redox reactions or caspase-3 inhibitors in the future.
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