The Ras proteins, Racing to the Beginning of the Road: The Search for the Origin of Cancer, 探索心靈與意識 and 粒子捕手 王贻芳
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Apr 10, 2017, 2:18:48 AM4/10/17
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to 語言、歷史及文化常識
The Ras proteins (K-Ras, N-Ras, and H-Ras) are GTPases that function as molecular switches for a variety of critical cellular activities and their function is tightly and temporally regulated in normal cells. Oncogenic mutations in the RAS genes, which create constitutively-active Ras proteins, can result in uncontrolled proliferation or survival in tumor cells.---- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4278912/ Robert Weinberg https://zh.wikipedia.org/zh-tw/%E7%BD%97%E4%BC%AF%E7%89%B9%C2%B7%E6%B8%A9%E4%BC%AF%E6%A0%BC https://en.wikipedia.org/wiki/Robert_Weinberg He is best known for his discoveries of the first human oncogene Ras and the first tumor suppressor gene Rb Signalling pathways are deregulated in cancer. Hanahan and Weinberg compared the signalling pathways to electronic circuits where transistors are replaced by proteins. The prototypical Ras pathway starts with an extracellular signal from growth factors (such as TGF-α). Other major extracellular signals are anti-growth factors (such as TGF-β), death factors (such as FASL), cytokines (such as IL-3/6)and survival factors (such as IGF1). Proteins inside the cell control the cell cycle, monitor for DNA damage and other abnormalities, and trigger cell suicide (apoptosis). Hanahan and Weinberg's signal pathway illustration is at Cell 100:59 https://en.wikipedia.org/wiki/Otto_Heinrich_Warburg Cancer hypothesis Main article: Warburg hypothesis
Warburg hypothesized that cancer growth is caused by tumor cells generating energy (as e.g. adenosine triphosphate / ATP) mainly by anaerobic breakdown of glucose (known as fermentation, or anaerobic respiration). This is in contrast to healthy cells, which mainly generate energy from oxidative breakdown of pyruvate. Pyruvate is an end product of glycolysis, and is oxidized within the mitochondria. Hence, and according to Warburg, cancer should be interpreted as a mitochondrial dysfunction.
Cancer, above all other diseases, has countless secondary causes. But, even for cancer, there is only one prime cause. Summarized in a few words, the prime cause of cancer is the replacement of the respiration of oxygen in normal body cells by a fermentation of sugar. — Otto H. Warburg,
Warburg continued to develop the hypothesis experimentally, and gave several prominent lectures outlining the theory and the data.
Today, mutations in oncogenes and tumor suppressor genes are thought to be responsible for malignant transformation, and the metabolic changes are considered to be a result of these mutations rather than a cause.
Warburg hypothesized that cancer growth is caused by tumor cells generating energy (as e.g. adenosine triphosphate / ATP) mainly by anaerobic breakdown of glucose (known as fermentation, or anaerobic respiration). This is in contrast to healthy cells, which mainly generate energy from oxidative breakdown of pyruvate. Pyruvate is an end product of glycolysis, and is oxidized within the mitochondria. Hence, and according to Warburg, cancer should be interpreted as a mitochondrial dysfunction.
Cancer, above all other diseases, has countless secondary causes. But, even for cancer, there is only one prime cause. Summarized in a few words, the prime cause of cancer is the replacement of the respiration of oxygen in normal body cells by a fermentation of sugar. — Otto H. Warburg,
Warburg continued to develop the hypothesis experimentally, and gave several prominent lectures outlining the theory and the data.
Today, mutations in oncogenes and tumor suppressor genes are thought to be responsible for malignant transformation, and the metabolic changes are considered to be a result of these mutations rather than a cause.
Feb 02 Thu 2017 《誰是我?意識的哲學與科學》/洪裕宏教授 諾貝爾物理學獎得主溫伯格(Steven Weinberg)非常樂觀地說:「目前我們尚未有最後的理論(the final theory),而且不太可能在短時間內發現最後的理論。但是我們一次又一次捕捉到一些暗示,告訴我們其到來之日不遠。物理學家在討論問題時,若發現漂亮的數學觀念與真實世界相干時,總覺得黑板之後有深刻的真理,預示存在一個最後的理論,使我們的數學觀念與世界如此相干。」溫伯格是一個科學的樂觀主義者,相信有一天可以發現最後的理論,解釋世界的一切事物。在特定的意義下,溫伯格認為物理科學能夠描繪完整的世界,人類的理性與悟性可以完全理解世界。
像溫伯格這樣的素樸樂觀論者不在少數,但也不乏悲觀論者,天文生物學家夏爾夫(Caleb A. Scharf)在《科學美國人》雜誌(Scientific American)提出幾個我們尚不瞭解、甚至可能永遠不能瞭解的問題,其中一個是為什麼這宇宙存在?為什麼這世界是有(being)而不是一無所有(nothingness)?霍根(John Horgan)在其《科學之終結》一書中認為,科學的主要領域如粒子物理學、宇宙學與演化生物學等,已發展至其顛峰。物理學家已無法超越量子力學與相對論,無法提出比大爆炸理論(The Big Bang Theory)更深刻的理論;生物學家已無法超越達爾文(Charles Darwin)的演化論與基因遺傳學。1999年時,霍根甚至悲觀地預測人類永遠沒有希望完全瞭解意識(consciousness)與心靈。
意識研究最重要的學會「意識科學研究學會(Association for the Scientific Study of Consciousness, ASSC)」於1997年成立,年會輪流在歐、美兩洲舉行。我從第4屆開始爭取於臺北舉辦年會的機會,原先學會執行委員會不願意到臺北召開年會,擔心學者因為距離太遠而不肯出席;但多數執行委員與我熟識,查默斯(David Chalmers)又是我在印地安那大學同學,委員會終於同意,並決議若臺北年會成功,以後便改為歐、美、亞三區輪流舉行。最後2008年在臺北主辦第12屆年會,並有300多篇論文發表,同時,臺北年會被譽為最好的一次年會,2016年阿根廷布宜諾斯艾利斯年會上,還再度被公開贊揚。這也促成了2011年日本京都年會和2017年北京年會。
惠勒說:「沒有空間,沒有時間,沒有重力,沒有電磁,沒有粒子,一無所有。我們又退回到柏拉圖、亞里斯多德、帕米尼德斯所困惑的偉大問題:怎麼會有宇宙?怎麼會有我們?怎麼會有所有東西?很高興對這些問題我們可以回答說:那是因為我們。」「『it from bit』意謂物理世界中的所有東西,終極上源自於非物質,即所有物理事物源自訊息。宇宙是參與式的宇宙。」惠勒認為,宇宙的存在是因為我們參與其中。我們不是旁觀者,世界不是客觀存在,而是由我們的經驗所創造。惠勒一生從物理論者一步步走向唯心論。
惠勒的訊息概念源自於向農(Cladue E. Shannon)的訊息理論。對向農而言,訊息指傳送一個訊息需要的比特量。例如每個比特不是0就是1。3個比特可以有8個不同的組合,因此3個比特可以傳送8個不同的信息。例如(0, 0, 0)、(0, 1, 0)……(1, 1, 1)。 其次,也可以說訊息就是用來測量不確定的熵(entropy)。不確定性或亂度愈高,訊息量愈大。
物理學家巴伯(Julian Barbour)認為這個意義下的訊息只是符號與機率,脫離它們所表徵的事物後,本身並無意義。所以向農的訊息理論只是關於形式符號的傳輸,並不滿足惠勒所需的訊息概念。日常語言中的訊息其實是事實內容,不是比特。另外,巴伯提到第3種訊息概念:內存的語意訊息。地質學有時間膠囊的概念,指化石、岩石等物。化石或岩層本身封存了過去的歷史記憶,地質學家可以「閱讀」其中的訊息。不過這些時間膠囊都是物體,不是比特。巴伯認為應該是「bit from it」而不是「it from bit」。
我認為惠勒的訊息概念有別於向農的概念。向農的訊息是被動的、消極的訊息,本身沒有內存意義,而要依賴有意識的觀察者賦予意義。惠勒的訊息是萬物之源,空間、時間、重力、電磁、粒子等等,都從訊息而來。如果訊息沒有內存意義,要靠行為者給予,那麼行為者才是萬物之源。這與「it from bit」大相逕庭。主動訊息是歷程,不是事物、狀態或性質。訊息不是被觀察的對象,非存在在意識之外,也非意識之內。它是產生這世界萬物及意識的基礎,是最根本的存在。既非物質,也非心靈,而是物理世界與心靈的源起。 h i 【新华社】记中科院高能物理研究所所长王贻芳:“粒子捕手” 2016-10-24 http://www.ihep.cas.cn/xwdt/cmsm/2016/201610/t20161024_4683505.html