用戶:Jsjsjs1111/沙盒
參考書目
- (英文)Morison, Samuel Eliot, History of United States naval operations in World War II: The Battle of the Atlantic, September 1939-May 1943, University of Illinois Press,線上電子版, 2001, ISBN 0252-069-633
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IUPAC名 aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa | |
若非註明,所有數據均出自標準狀態(25 ℃,100 kPa)下。 |
2011年统计用区划代码和城乡划分代码:石洞街道. 中華人民共和國國家統計局. 2011.
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此用戶關注或感興趣於化學。 |
DNA UV mutation.gif DesaminierungCtoU.png DNA intercalation2.jpg Photodimer.png Composite transposon.svg
60.251.107.200
毒物學和毒物 |
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致癌物可以是任何化學物質、放射性同位素,或者輻射,它們直接參與癌症的惡化或者促進癌細胞的增殖的。致癌物質的致癌性可能是因為它們有對細胞代謝過程或基因組的破壞能力。許多仿色性物質被認為是致癌物,但他們的致癌性來源於它們發出來的輻射,如γ-射線或α-粒子。 Common examples of carcinogens are inhaled asbestos, certain dioxins, and tobacco smoke.
Carcinogens may increase the risk of getting cancer by altering cellular metabolism or damaging DNA directly in cells, which interferes with biological processes, and induces the uncontrolled, malignant division, ultimately leading to the formation of tumors. Usually DNA damage, if too severe to repair, leads to programmed cell death, but if the programmed cell death pathway is damaged, then the cell cannot prevent itself from becoming a cancer cell.
There are many natural carcinogens. Aflatoxin B1, which is produced by the fungus Aspergillus flavus growing on stored grains, nuts and peanut butter, is an example of a potent, naturally-occurring microbial carcinogen. Certain viruses such as Hepatitis B and human papilloma viruses have been found to cause cancer in humans. The first one shown to cause cancer in animals is Rous sarcoma virus, discovered in 1910 by Peyton Rous.
Benzene, kepone, EDB, asbestos, and the waste rock of oil shale mining have all been classified as carcinogenic.[1] As far back as the 1930s, industrial smoke and tobacco smoke were identified as sources of dozens of carcinogens, including benzo[a]pyrene, tobacco-specific nitrosamines such as nitrosonornicotine, and reactive aldehydes such as formaldehyde—which is also a hazard in embalming and making plastics. Vinyl chloride, from which PVC is manufactured, is a carcinogen and thus a hazard in PVC production.
Co-carcinogens are chemicals that do not necessarily cause cancer on their own, but promote the activity of other carcinogens in causing cancer.
After the carcinogen enters the body, the body makes an attempt to eliminate it through a process called biotransformation. The purpose of these reactions is to make the carcinogen more water-soluble so that it can be removed from the body. But these reactions can also convert a less toxic carcinogen into a more toxic one.
DNA is nucleophilic, therefore soluble carbon electrophiles are carcinogenic, because DNA attacks them. For example, some alkenes are toxicated by human enzymes to produce an electrophilic epoxide. DNA attacks the epoxide, and is bound permanently to it. This is the mechanism behind the carcinogenity of benzo[a]pyrene in tobacco smoke, other aromatics, aflatoxin and mustard gas.
Radiation
CERCLA identifies all radionuclides as carcinogens, although the nature of the emitted radiation (alpha, beta, gamma, or neutron and the radioactive strength), its consequent capacity to cause ionization in tissues, and the magnitude of radiation exposure, determine the potential hazard. Carcinogenity of radiation depends of the type of radiation, type of exposure and penetration. For example, alpha radiation has low penetration and is not a hazard outside the body, but are carcinogenic when inhaled or ingested.
For example, Thorotrast, a (incidentally-radioactive) suspension previously used as a contrast medium in x-ray diagnostics, is a potent human carcinogen known because of its retention within various organs and persistent emission of alpha particles. Marie Curie, one of the pioneers of radioactivity, died of cancer caused by radiation exposure during her experiments.
Not all types of electromagnetic radiation are in fact carcinogenic. Low-energy waves on the electromagnetic spectrum are generally not, including radio waves, microwave radiation, infrared radiation and visible light. Higher-energy radiation, including ultraviolet radiation (present in sunlight), x-rays, and gamma radiation, generally is carcinogenic, if received in sufficient doses.
Several published studies suggest a link between exposure to light at night and risk of breast cancer, due to suppression of the normal nocturnal production of melatonin.[2][3] In 1978 Cohen et al. proposed that reduced production of the hormone melatonin might increase the risk of breast cancer and citing "environmental lighting" as a possible causal factor.[4] Researchers at the National Cancer Institute (NCI) and National Institute of Environmental Health Sciences have concluded a study that suggests that artificial light during the night can be a factor for breast cancer.[5] A good review of current knowledge of the health consequences of exposure to artificial light at night and an explanation of the causal mechanisms has been published in the Journal of Pineal Research in 2007.[6]
Substances or foods irradiated with electrons or electromagnetic radiation (such as microwave, X-ray or gamma) are not carcinogenic.citation needed No "radiation" remains, just like no light remains in room after you turn out the light. (In contrast, non-electromagnetic neutron radiation produced inside nuclear reactors can produce secondary radiation by making bombarded substances radioactive.)
In other words, there is no possibility of getting cancer from consuming the irradiated food.citation needed
Carcinogens in prepared food
Cooking food at high temperatures, for example grilling or barbecuing meats, can lead to the formation of minute quantities of many potent carcinogens that are comparable to those found in cigarette smoke (i.e., benzo[a]pyrene).[7] Charring of food resembles coking and tobacco pyrolysis, and produces similar carcinogens. There are several carcinogenic pyrolysis products, such as polynuclear aromatic hydrocarbons, which are converted by human enzymes into epoxides, which attach permanently to DNA. Pre-cooking meats in a microwave oven for 2–3 minutes before grilling shortens the time on the hot pan, and removes heterocyclic amine (HCA) precursors, which can help minimize the formation of these carcinogens.[8]
Reports from the Food Standards Agency have found that the known animal carcinogen acrylamide is generated in fried or overheated carbohydrate foods (such as french fries and potato chips).[9] Studies are underway at the FDA and European regulatory agencies to assess its potential risk to humans.
Dr. T. Colin Campbell argues in The China Study that the milk protein casein, found in milk and many prepared foods, is also a carcinogen.[10] However, independent studies report that casein and other milk proteins protect against cancer.[11]
Carcinogens in cigarettes
Tobacco smoke contains over 4000 chemical compounds, many of which are carcinogenic or otherwise toxic.[12]
Circadian disruption
"Shiftwork that involves circadian disruption" was listed, in 2007, as a probable carcinogen by the World Health Organization's International Agency for Research on Cancer. (IARC Press release No. 180).[13] Multiple studies have documented a link between night shift work and the increased incidence of breast cancer.[14][15][16][17] Circadian disruption by exposure to light at night suppresses the production of the hormone melatonin which leads to reduction in cellular immune defense and surveillance necessary for protection from development of cancers. Melatonin also seems to have a direct protective effect against cancer possibly in part because of its strong anti oxidant properties.[18]
Mechanisms of carcinogenicity
Carcinogens can be classified as genotoxic or nongenotoxic. Genotoxins cause irreversible genetic damage or mutations by binding to DNA. Genotoxins include chemical agents like N-nitroso-N-methylurea (MNU) or non-chemical agents such as ultraviolet light and ionizing radiation. Certain viruses can also act as carcinogens by interacting with DNA.
Nongenotoxins do not directly affect DNA but act in other ways to promote growth. These include hormones and some organic compounds.[19]
Classification of carcinogens
IARC | GHS | NTP | ACGIH | EU |
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Group 1 | Cat. 1A | Known | A1 | Cat. 1 |
Group 2A | Cat. 1B | Reasonably suspected |
A2 | Cat. 2 |
Group 2B | ||||
Cat. 2 | A3 | Cat. 3 | ||
Group 3 | ||||
A4 | ||||
Group 4 | A5 |
International Agency for Research on Cancer
The International Agency for Research on Cancer (IARC) is an intergovernmental agency established in 1965, which forms part of the World Health Organization of the United Nations. It is based in Lyon, France. Since 1971 it has published a series of Monographs on the Evaluation of Carcinogenic Risks to Humans[20] that have been highly influential in the classification of possible carcinogens.
- Group 1: the agent (mixture) is definitely carcinogenic to humans. The exposure circumstance entails exposures that are carcinogenic to humans.
- Group 2A: the agent (mixture) is probably carcinogenic to humans. The exposure circumstance entails exposures that are probably carcinogenic to humans.
- Group 2B: the agent (mixture) is possibly carcinogenic to humans. The exposure circumstance entails exposures that are possibly carcinogenic to humans.
- Group 3: the agent (mixture or exposure circumstance) is not classifiable as to its carcinogenicity to humans.
- Group 4: the agent (mixture) is probably not carcinogenic to humans.
Globally Harmonized System
The Globally Harmonized System of Classification and Labelling of Chemicals (GHS) is a United Nations initiative to attempt to harmonize the different systems of assessing chemical risk which currently exist (as of March 2009) around the world. It classifies carcinogens into two categories, of which the first may be divided again into subcategories if so desired by the competent regulatory authority:
- Category 1: known or presumed to have carcinogenic potential for humans
- Category 1A: the assessment is based primarily on human evidence
- Category 1B: the assessment is based primarily on animal evidence
- Category 2: suspected human carcinogens
U.S. National Toxicology Program
The National Toxicology Program of the U.S. Department of Health and Human Services is mandated to produce a biennial Report on Carcinogens.[21] As of March 2009, the latest edition was the 11th report (2005).[1] It classifies carcinogens into two groups:
- Known to be a human carcinogen
- Reasonably anticipated to be a human carcinogen
American Conference of Governmental Industrial Hygienists
The American Conference of Governmental Industrial Hygienists (ACGIH) is a private organization best known for its publication of threshold limit values (TLVs) for occupational exposure and monographs on workplace chemical hazards. It assesses carcinogenicity as part of wider assessment of the occupational hazards of chemicals.
- Group A1: Confirmed human carcinogen
- Group A2: Suspected human carcinogen
- Group A3: Confirmed animal carcinogen with unknown relevance to humans
- Group A4: Not classifiable as a human carcinogen
- Group A5: Not suspected as a human carcinogen
European Union
The European Union classification of carcinogens is contained in the Dangerous Substances Directive and the Dangerous Preparations Directive. It consists of three categories:
- Category 1: Substances known to be carcinogenic to humans.
- Category 2: Substances which should be regarded as if they are carcinogenic to humans.
- Category 3: Substances which cause concern for humans, owing to possible carcinogenic effects but in respect of which the available information is not adequate for making a satisfactory assessment.
This assessment scheme is being phased out in favor of the GHS scheme (see above), to which it is very close in category definitions.
Procarcinogen
A procarcinogen is a precursor to a carcinogen. One example is nitrites when taken in by the diet. They are not carcinogenic themselves, but turn into nitrosamines in the body, which are carcinogenic.[22]
Common carcinogens
Occupational carcinogens
Occupational carcinogens are agents that pose a risk of cancer in several specific work-locations:
Carcinogen | Associated cancer sites or types | Occupational uses or sources |
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Arsenic and its compounds |
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Asbestos |
Not in use, but still found in:
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Benzene | ||
Beryllium and its compounds |
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Cadmium and its compounds |
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Hexavalent chromium(VI) compounds |
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Ethylene oxide |
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Nickel |
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Radon and its decay products |
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Vinyl chloride |
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Shiftwork that involves
circadian disruption[13] |
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Involuntary smoking (Passive smoking)[23] |
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Unless else specified in boxes, then ref is: [24] |
Others
- Gasoline (contains aromatics)
- Lead and its compounds
- Alkylating antineoplastic agents (chemotherapy)
- Other alkylating agents (e.g. dimethyl sulfate)
- Ultraviolet radiation from the sun and UV lamps
- Other ionizing radiation (X-rays, gamma rays, etc.)
See also
- Industrial Union Department v. American Petroleum Institute
- International Agency for Research on Cancer
- Mutagen
- Possible carcinogen
- Teratogen
- Warburg hypothesis
RE:唔好意思
您還是說普通話吧(因為我覺得打廣州話很麻煩)…… 作為一個新人(按照註冊賬號時間來說),對於這個我剛註冊就參與的投票討論,我認為主要問題是這幾點:
- Msuker肯定是有錯的,他不應該以咄咄逼人的語氣討論,不應諷刺別人,同時他也似乎沒能做到WP:善意推定(不過您作為一個老維基人應該知道他一直說話都是這樣的)。當然,他在討論時儘管「可怕」,但他沒有違反WP:CIV(可能是因為他比較喜歡說別人人身攻擊因而自己也比較注意吧)。嚴格上來說,他儘管有錯,但並沒有違反任何成文條款(WP:AGF只是指引)。這裏也引用費勒姆兄的原話:「人身攻擊的定義很廣泛,如果你認定我部份內容是有人身攻擊的話,那麼你會不會認為是假定惡意?」
- Msuker說話很強硬、辛辣,讓人很難受(用廣州話說就是「好竄」),這點我承認,他以前也因此招了不少麻煩——他與某S君、華德禹、Jackycheung、Clithering和Ws227的大量衝突,看他的封禁紀錄也是「罪行累累」[1]。但在我看來,他在討論中或許有「攻擊別人」,但沒有髒話,而且也是有理有據(這不是我個人的觀點,其他人也這樣說過[2])。
- Msuker之所以在這個投票中又一次如此激動,不能僅僅怪罪於他,主要問題還是在某S君身上。某S君從一開始在這個投票中就不斷「玩弄規則」,先是在投票時使用「全體票數」來拖,然後又說Msuker拉票要封禁,最後又在投票結束後說「對大家不公平」,被Msuker駁倒又轉移話題說這個投票應該留給香港人自己投(作為發起人的他自己都不是香港人),這幾點你應該也看得到。像我作為一個使用粵語的廣州人,本來也想投選項2,但看到他的無理取鬧,迫使我改變了主意(就像Shizhao罷免案里那些看不慣支持者「政治審查」的理由而改票的人一樣)。輸打贏要,從某種程度上來說,一切問題都是他引起的。
- 這次投票的討論中大家都比較激動,而我特別欣賞的是LUFC。在這個討論中,儘管他支持香港譯名,但他一直很理性,而且在某S同學耍賴之時也勸說了他[3]。
- 最後總結這次討論:不論Msuker的所作所為有多不妥,投票結果出來了,這就是事實,無法否認,我們不能夠因噎廢食。唉,也希望這次爭論能儘快結束,大家能夠儘快回到正常的條目編寫中,而不是在這些無謂地方上爭論如此長的時間(現在投票結果遲遲不出導致的又是衝突——見Talk:洛達·安塔爾、Talk:伊戈·古斯域治)。
以上就是我作為一個新人對此次討論的意見,如有不當,還請費勒姆兄海涵。PS:請問您為什麼找我問這個問題,是不明白我為什麼一直支持Msuker嗎?如果是的話,理由見上面2、3條。
另外還有,Msuker這段話真的說得很有道理:
什麼樣的人做什麼樣的事,不多說了。我只想說,諸位管理員、行政員,難道真的就為了怕惹事,怕某些人惦記,默不作聲,視方針、共識、投票、討論結果於不顧?這是你們申請做管理員、行政員時候的初衷?
不知道您是否也這樣認為呢?—CHEM.is.TRY 2010年5月28日 (五) 12:44 (UTC)
Notes
- ^ 1.0 1.1 Report on Carcinogens, Eleventh Edition; U.S. Department of Health and Human Services, Public Health Service, National Toxicology Program (2005).
- ^ Scott Davis; Dana K. Mirick; Richard G. Stevens. Night Shift Work, Light at Night, and Risk of Breast Cancer. Journal of the National Cancer Institute. 2001, 93 (20): 1557–1562. PMID 11604479. doi:10.1093/jnci/93.20.1557. 已忽略未知參數
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(幫助) - ^ Eva S. Schernhammer; Francine Laden; Frank E. Speizer; Walter C. Willett; David J. Hunter; Ichiro Kawachi; Graham A. Colditz. Rotating Night Shifts and Risk of Breast Cancer in Women Participating in the Nurses' Health Study. Journal of the National Cancer Institute. 2001, 93 (20): 1563–1568. PMID 11604480. doi:10.1093/jnci/93.20.1563. 已忽略未知參數
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(幫助) - ^ Cohen M, Lippman M, Chabner B. Role of pineal gland in aetiology and treatment of breast cancer. Lancet 1978;2:14–16.
- ^ The Independent Avoid breast cancer. Sleep in the dark...
- ^ Navara KJ, Nelson RJ (2007) The dark side of light light at night: physiological, epidemiological, and ecological consequences. J. Pineal Res. 2007; 43:215–224
- ^ Wei Zheng, Deborah R Gustafson, Rashmi Sinha, James R Cerhan, et al. "Well-done meat intake and the risk of breast cancer." Journal of the National Cancer Institute. Oxford: Nov 18, 1998.Vol. 90, Iss. 22; pg. 1724, 6 pgs.
- ^ National Cancer Institute, 2004 analysis and recommendations
- ^ Acrylamide.
- ^ Thomas M., II Campbell; Campbell, Thomas M.; Colin T., PH D. Campbell. The China study: the most comprehensive study of nutrition ever conducted and the startling implications for diet, weight loss and long-term health. Benbella Books. 2005. ISBN 1-932100-38-5.
- ^ Parodi PW. A role for milk proteins and their peptides in cancer prevention. Current Pharmaceutical Design. 2007, 13 (8): 813–28. PMID 17430183. doi:10.2174/138161207780363059.
- ^ http://quitsmoking.about.com/cs/nicotineinhaler/g/carbonmonoxide.htm
- ^ 13.0 13.1 IARC Monographs Programme finds cancer hazards associated with shiftwork, painting and firefighting, International Agency for Research on Cancer (PDF), [2009-01-24]
- ^ Schernhammer E, Schulmeister K. Melatonin and cancer risk: does light at night compromise physiologic cancer protection by lowering serum melatonin levels? Br J Cancer 2004;90:941–943.
- ^ Hansen J. Increased breast cancer risk among women who work predominantly at night. Epidemiology 2001; 12:74–77.
- ^ Hansen J. Light at night, shiftwork, and breast cancer risk.J Natl Cancer Inst 2001; 93:1513–1515.
- ^ Schernhammer E, Laden F, Speizer FE et al. Rotating night shifts and risk of breast cancer in women participating in the nurses' health study. J Natl Cancer Inst 2001; 93:1563–1568.
- ^ Navara KJ, Nelson RJ (2007) The dark side of light light at night: physiological, epidemiological, and ecological consequences. J. Pineal Res. 2007; 43:215–224
- ^ The Gale Encyclopedia of Cancer: A guide to Cancer and its Treatments, Second Edition. Page no. 137.
- ^ IARC Monographs
- ^ Section 301(b)(4) of the Public Health Service Act, as amended by Section 262, Pub. L. 95–622.
- ^ Web definitions for Procarcinogen
- ^ Tobacco Smoke and Involuntary Smoking, IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Volume 83 (2004).
- ^ Table 6-2 in: Mitchell, Richard Sheppard; Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson. Robbins Basic Pathology. Philadelphia: Saunders. 2007. ISBN 1-4160-2973-7. 8th edition.
External links
- U.S. National Toxicology Program's Report on Carcinogens
- Recognized Carcinogens
- American Cancer Society
- Database of Rodent Carcinogens
- Comparing Possible Cancer Hazards from Human Exposures to Rodent Carcinogens
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