Share on LinkedIn There is a well-known AI (Artificial Intelligence) phenomenon, called Eliza Effect, stating that people may over-interpret the machine results, reading between lines for meanings that do not originally exist. Here is the entry in Wikipedia: The ELIZA effect , in computer science , is the tendency to unconsciously assume computer behaviors are analogous to human behaviors. In its specific form, the ELIZA effect refers only to the susceptibility of people to read far more understanding than is warranted into strings of symbols — especially words — strung together by computers. ...... More generally, the ELIZA effect describes any situation where, based solely on a system's output, users perceive computer systems as having intrinsic qualities and abilities which the software controlling the (output) cannot possibly achieve or assume that reflect a greater causality than they actually do. ...... The discovery of the ELIZA effect was an important development in artificial intelligence , demonstrating the principle of using social engineering rather than explicit programming to pass a Turing test . ( https://en.wikipedia.org/wiki/ELIZA_effect ). In fact, for human intelligence, there also exists a mirror effect, what I name the Anti-Eliza effect, which relates to the tendency to unconsciously mythify human capabilities, by often over-interpreting output of human agents for meanings which do not originally exist. The Anti-Eliza effect disregards the fact that more than 90% of the human intelligent activities are actually mechanic or algorithmic bu nature, supported by access to the memory of a knowledge base. In fact, the frequently observed Eliza effect and the Anti-Eliza effect are two sides of the same coin, based most likely on similar cognitive grounds of human mind. The human intelligence in effect can hardly stand undergoing decomposition for a few rounds before it shows its true identity of possibly less than one percent of inspiration, with 99% mechanical processes. When they are blended together, they may manifest themselves inside a human body to be worshiped as a master or genius. There is no way for the Artificial Intelligence to target that one percent. It is neither possible nor necessary. Hereby let me present this new concept of the Anti-Eliza effect in AI, to be associated with the human habit and nature of self-mythification. Such human self-mythification is exemplified by reading the human intelligent output for meanings which simply do not exist and by over-exaggerating the significance of human spirituality. For example, for the same piece of work, if we are told the work is a result of a machine, we will instinctively belittle it, in order to maintain the human dignity or arrogance. If the work is believed to be a rare antique or artifact of a human artist, it will draw numerous interpretations with amazing appreciation. The Anti-Eliza effect shows itself widely in the domain of art and literature review. For the genre of abstract art, this effect is rationalized: it is actually expected for different people to read different meanings out of the same art, independent of what the original author intended for. That is considered to be part of the original value of this type of work. The ability of reading an artistic work for many meanings which were not intended for is often considered to be the necessary quality of a professional art reviewer. It not only requires courage but also is often futile to point out that the emperor has no clothes on and the work does not make sense, or has no meanings as interpreted by reviewers. The theory of aesthetics involving the abstract art has no needs to depend on reality checking at all. In my understanding, the Anti-Eliza effect is manifestation of mysticism, and mysticism is very close to some nature of human beings. This is a huge topic, that calls for further exploration in AI to see the entire picture and scope of this effect. The Anti-Eliza effect is believed to be an important basic concept in the field of AI, as significant as its mirror concept of the Eliza effect. This is by no means to deny the supremacy of human mind, nor to deny the humanity shined by that one percent of spirituality in our intelligent output. Only the most stupid people would be so self-denial, attacking human dignity. However, for either science or engineering, everything needs to be verified or proved. In the AI work, the first thing we do in practice is to peel off what can be modeled by a machine from what is truly unique to humans only. We will then make the machine mimic or model that 99% of materials or processes in human intelligent behaviors, while keeping a distance from, and maintaining a high regard for, the 1% true human wisdom. As is observed, the routine intelligent activities of mankind will be approximated and modeled more and more in AI, very much like a silkworm eating more and more parts of mulberry leaves. With each progressive territory expansion of AI, what was originally thought of as truly intelligent is quickly decomposed into an algorithm of solutions which no longer belong to the human unique wisdom. If the nature of mankind is simply a hybrid of 1% from the holy spirit and 99% from some fundamentally mechanical devices, then in the end, it is inevitable that machines will one day replace the 99% of human intelligent labor. From a different angle, any implementable AI-oriented proximation to the human intelligent activities is by nature not true intelligence. Obviously, as time goes by, more and more such proximation will be programmed into machines to replace the mediocre human performers. But there will always be something that can never be computerized, which is the true human intelligence (synonyms of this include wisdom, spirituality, inspiration, soul, etc). The difficulty now lies in that for majority of specific intelligent tasks, they are still mixed together with no clear separation between spirit and mechanical materials. We can hardly define or see clearly what that spirit (the core intelligence unique to mankind) is, unless AI accumulates its modeling successes over time to a point of diminishing return. Before that happens, we humans tend to continue our mythification of our own abilities, and classifying those abilities as uniquely human. In other words, the Anti-Eliza effect will run a long long time based on the human nature of mythification. Let us look at the history for a brief review of some fundamental abilities which have long been believed to be human intelligence. This review will help us see how this effect has evolved over time. In the pre-computing era,the arithmetic abilities were highly regarded. The few people with exceptional arithmetic performance were generally considered the most intelligent men. After calculators and computers were invented, this was the first myth to break down. No one in today's society will consider a calculator an intelligent being. Following the calculating power is the memorization capacity that has also been believed to be an incredible intelligence of the human brain for a long time. In Ancient times, people with extraordinary mental arithmetic ability and outstanding memory capacity were often worshiped as genius masters or living gods (of course, memorization involves not only the storage capacity, but also the accompanying retrieval abilities to access the storage). As a matter of fact, many intelligent machines (e.g. some expert systems) implemented in the AI history come down at the core to a customized search algorithm plus a memory of formalized domain knowledge. The modelled intelligent activities have thus been demystified from the presumed Anti-Eliza effect. For an illustration, I would like to present the case of natural language parsing to see how much human intelligence is really involved. The ability to parse a natural language in grammatical analysis is widely recognized in the NLP community and beyond as a key to the natural language understanding and the human intelligence. Fortunately, modeling this ability has been one of the major professional tasks in my entire career in the last two decades. So I believe that I have the expertise and knowledge to uncover the true picture involved in this area. As a seasoned professional, I can responsibly tell you, 99% of the human parsing capability can be modeled by a computer very well, almosy indistinguishable from a human grammarian. The human grammatical analysis of the underlying linguistic structures can be closely assimilated by a linguistic parsing algorithm based on the language knowledge of vocabulary, usage and rules. Both our English parser and Chinese parser, which I designed and led the team to have developed, are close to the level of being able to parse 99% of random text into reasonable linguistic structures. As a key human intelligence, this type of modeling performance was unimaginable, like a miracle, but there lie some easily measurable benchmarks in practice. Stepping back from parsing abilities to the metaphysical level, what I want to say here is that, much of what we originally thought of as deep intelligence cannot stand decomposition either. Every step of decomposition in the AI research progress has helped to reveal the true picture of human intelligent behaviour which is usually not what we used to believe. It has turned out to be a wonderful and eye-opening experience in the career of most AI and NLP researchers in the last few decades. Until things are decomposed in AI, there has been a natural Anti-Eliza effect that seems to control or dominate the perception of most types of human intelligent activities in the minds of not only the general population but us AI-insiders as well. Before we embark on exploring an intelligent task from the AI perspective, we often cannot help mythifying the seemingly marvelous intelligence due to the Anti-Eliza effect. But most of us end up with being able to formalize a solution that is algorithmic and implementable in computer with a memory of some form of knowledge representation. We will then realize there is really little magic in the process. Most probably, I believe, mysticism and self-mythification are just part of human nature, hence the widespread manifestation of the Anti-Eliza effect. translated by the original author Wei Li and from his original Chinese version here: 【新智元笔记：反伊莉莎效应，人工智能的新概念】 【相关】 【新智元笔记：反伊莉莎效应，人工智能的新概念】 MT 杀手皮尔斯（翻译节选） 【置顶：立委科学网博客NLP博文一览（定期更新版）】
On the intrinsic hardness of a metallic film/substrate system: Indentation size and substrate effects Z.S. Ma, Y.C. Zhou, S.G. Long, C. Lu To examine effects of indentation size and substrate on the hardness determination of thin films, two typical types of hard film/soft substrate (Ni/Fe) and soft film/hard substrate (Al/Si and Al/glass) systems are investigated. A simple model is proposed to predict the intrinsic hardness of thin films, which allows a more accurate fitting to empirical data and the estimation of ultimate film hardness. The model can be used to interpret indentation data and extrapolate the indentation depth-hardness curve to an important region where indentation depth lies between 1% to 5 times of film thickness. The results are well consistent with the evolving trend of composite hardness obtained from experiments and numerical results by finite element analysis. IJP.pdf
The Kirkendall effect. At the boundary between two solids diffusing into each other at different rates, for example zinc and copper, their alloy (brass) grows in the direction of the faster-moving species (zinc). Unfilled voids are left behind and coalesce into large pores. Discovered in 1942, the Kirkendall effect describes what happens when two solids diffuse into each other at different rates. The boundary between two metals, zinc and copper for example, is formed by a growing layer of alloy brass, in this case which expands in the direction of the faster-moving species, zinc. This was the clue to Ernest Kirkendall's discovery that the atoms of the two solids don't change places directly; rather diffusion occurs where voids open, making room for atoms to move in. In the wake of the faster-moving material, large pores or cavities form as unfilled voids coalesce. On the nanoscale, the Kirkendall effect explains why a fast-diffusing cobalt nanocrystal leaves a hollow center behind as it moves into a surrounding sulfide-compound shell. The nanospheres were remarkably uniform: depending on the proportions of the starting materials, their hollow centers were 40 to 70 percent as big as the initial crystal, but hole size varied no more than 13 percent in any given batch. This uniformity and versatility suggested a wide range of applications including drug delivery systems, optics, electronics, and selective chemical reactors, all on the nanoscale. Ref. Formation of hollow nanocrystals through the nanoscale Kirkendall effect, by Yadong Yin, Robert M. Rioux, Can K. Erdonmez, Steven Hughes, Gabor A. Somorjai, and A. Paul Alivisatos in Science, 30 April 2004
一、effect是否可数？ 具体是可数还是不可数要在具体语言环境中体现,你可以只记一方面,记住可数的,其他方面大多为不可数了.在牛津词典的标注中,一种含义的注释前面都有 ,所以,此题不能完全绝对的回答 1) effect作结果解时，是可数名词，与cause相对 例句：He dwelt on the war from effect to cause. 他评述了战争的前因后果。 2) effect 作作用；影响解时，表示对产生作用，要用介词on。若前面有动词give，后可接介词to。 例句：He felt sick from the effect of weather. 他因天气变化感到不适。 Our warning produced no effect on him at all. 我们的警告对他未起丝毫作用。 A word from the teacher will have a great effect on our son. 老师的话会对我们的儿子起很大作用。 Flowers arranged in a vase give a charming effect to a room. 插花给房间增添了色彩。 联想记忆：含有effect的短语： 1) 表示无效的短语：be of no effect，to no effect，with little/no effect，without effect 2) 表示实现；实行；实施的短语： bring into(to) effect，carry into effect， give effect to, put into effect，come(go) into effect， in effect 辨析：effect和affect affect只能用作动词，表示to have an effect on强调影响的动作，后面常跟具体名词作宾语， 强调发生对有害的影响。 例句：The climate affected his health. 气候对他的健康产生影响。 Failures did not affect him at all. 失败未对他造成影响。 effect既可作动词，也可作名词，表示to produce as an effect强调达到的效果，后面常 跟表示改进变化的宾语。 例句：They effected their plan with much difficulty. 他们历尽千辛完成了计划。 二、affect和effect的区别 effect n.结果, 效果, 作用, 影响, (在视听方面给人流下的)印象 vt.招致, 实现, 达到(目的等) impact n.碰撞, 冲击, 冲突, 影响, 效果 vt.挤入, 撞击, 压紧, 对...发生影响 affect vt.影响, 感动, 侵袭, 假装 influence n.影响, 感化, 势力, 有影响的人(或事), (电磁)感应 vt.影响, 改变 What is the difference between affect and effect? Answer: Affect is a verb that means to have an influence on or to bring about a change in: Does second hand smoke affect the health of all of us? Effect can also function as a verb meaning to execute: Only the president can effect such a change. However, effect is most often used as a noun meaning, result: The drug did not affect the disease, and it had several adverse side effects. Rule of thumb: if you need a verb, nine times out of ten you will used affect; if you need a noun, you will always use effect. 问题102：affect和effect有什么区别？ 回答：affect是一个动词，意思是对有影响或给带来变化。 例如：Does second hand smoke affect the health of all of us? effect有时也可以作动词用，意为执行。 例如：Only the president can effect such a change. 但是，effect在大多数情况下都被用作名词，意为结果。 例如：The drug did not affect the disease, and it had several adverse side effects. 一个简便的原则就是如果你需要一个动词的话，十之八九选用affect，如果需要一个名词，则通常使用effect. affect vt.①影响②打动，感动③(疾病)侵袭 词汇辨析affect,effect,influence： affect常用作动词，effect常用作名词(意为影响)：to affect sth.=to have an effect on sth. effect 作动词时很正式，意为产生，带来(结果)，这个产生或带来的结果常常是某人所希望的。 influence指通过行动、榜样等对他人产生潜移默化的影响或作用，注重影响的结果。 记忆方法形似词：effect n.影响；effort n.努力 词根记忆af(使)+fect（做）使人做影响 effect 43 n.①结果②效果，作用vt.产生，招致 经典例句The effect speaks, the tongue needs not.事实胜于雄辩。 考点提要in effect = in fact 实际上；take effect = come into force 实施，生效；to that effect 大意如此 记忆方法fect(作用)affect v.影响；effect n.影响 词根记忆ef(出)+fect（做）做出来生效，效果
Affect 和 Effect 尽管 affect 和 effect 的发音很像，但用法却有所不同。 Affect绝大多数情况下作动词使用，意为作用于 (to influence) Effect绝大多数情况下作名词使用，意为行动的结果 (the result of some action) 但是，effect在作动词使用时有使发生或造成的含义，而affect在作名词使用时，含义为情绪反应或感动。为避免混淆，建议在使用时取他们的一般含义。 示例 Luckily, the medicine did not adversely affect the patient. 【 正确 】 Luckily, the medicine did not adversely effect the patient. 【 错误 】 Many scientists believe that global warming is the effect of greenhouse-gas emissions. 【 正确 】 Many scientists believe that global warming is the affect of greenhouse-gas emissions. 【 错误 】 练习 请根据以上总结改写下面的句子。 Smoking badly affects/effects your health, while exercise has the opposite affect/effect. The inhibitor affected/effected the concentration? The photovoltaic affect/effect is the process of a solar cell converting sunlight into electricity.
砷是一种类金属元素,以化合物的形式广泛分部于地壳、土壤、水、大气、食物及生物体内。砷对健康的影响具有多样性,例如缺砷可致动物繁殖减少、出生率降低、发育迟缓],授乳期间由于心血管受损而不断死亡。大量的动物实验研究亦证明,砷对动物的生长发育可能是必须的 。另外,祖国医学认为,适量的食砷具有美容、健体、延年益寿之功效,而过量摄入砷则可导致砷中毒。因此,充分认识砷的生物学作用具有极其重要的意义。砷的化学性质及代谢砷的化学性质很复杂,化合物众多,在自然界中以As3-、As-、As0、As+、、As3+、As5+的形式存在。 （在电子期刊看到本文，特此贴出。） Health effects of arsenic if (window.showTocToggle) { var tocShowText = "show"; var tocHideText = "hide"; showTocToggle(); } Introduction Arsenic is an element that is widely distributed in the Earth's crust. Elemental arsenic is ordinarily a steel grey, metal-like material that occurs naturally. However, arsenic is usually found in the environment combined with such other elements as oxygen, chlorine, and sulfur. Arsenic combined with these elements is called inorganic arsenic. Arsenic combined with carbon and hydrogen is referred to as organic arsenic. Understanding the difference between inorganic and organic arsenic is important because some of the organic forms are less harmful than the inorganic forms. Most inorganic and organic arsenic compounds are white or colorless powders that do not evaporate. They have no smell, and most have no special taste. You usually cannot tell, therefore, if arsenic is present in your food, water, or air. Inorganic arsenic occurs naturally in soil and in many kinds of rock, especially in minerals and ores that contain copper or lead. When these ores are heated in smelters, most of the arsenic goes up the stack and enters the air as a fine dust. Smelters may collect this dust and take out the arsenic as a compound called arsenic trioxide (As 2 O 3 ). However, arsenic is no longer produced in the United States; all of the arsenic used in the United States is imported. Presently, about 90% of all arsenic produced is used as a preservative for wood to make it resistant to rotting and decay. The preservative is copper chromated arsenic (CCA) and the treated wood is referred to as pressure-treated. In 2003, U.S. manufacturers of wood preservatives containing arsenic began a voluntary transition from CCA to other wood preservatives that do not contain arsenic in wood products for certain residential uses; for example, play structures, picnic tables, decks, fencing, and boardwalks. This phase-out was completed on December 31, 2003; however, wood treated prior to this date could still be usedand existing structures made with CCA-treated wood would not be affected. CCA-treated wood products continue to be used in industrial applications. It is not known whether, or to what extent, CCA-treated wood products may contribute to exposure of people to arsenic. In the past, inorganic arsenic compounds were predominantly used as pesticides, primarily on cotton fields and in orchards. Inorganic arsenic compounds can no longer be used in agriculture. However, organic arsenic compounds, namely cacodylic acid, disodium methylarsenate (DSMA), and monosodium methylarsenate (MSMA), are used, as yet, as pesticidesprincipally on cotton. Some organic arsenic compounds are used as additives in animal feed. Small quantities of arsenic metal are added to other metals to form metal mixtures or alloys with improved properties. The greatest use of arsenic in alloys is in lead-acid batteries for automobiles. Another important use of arsenic compounds is in semiconductors and light-emitting diodes. Pathways of arsenic to the environment Figure 1: Arsenic Concentrations in Groundwater Resources. (Source: U.S. Geological Survey) Arsenic occurs naturally in soil and minerals and it therefore may enter the air, water, and land from wind-blown dust and may get into water from runoff and leaching. Volcanic eruptions are another source of arsenic. Arsenic is associated with ores mined for metals, such as copper and lead, and may enter the environment during the mining and smelting of these ores. Small amounts of arsenic also may be released into the atmosphere from [[coal-fired power plants and incinerators because coal and waste products often contain some arsenic. Arsenic cannot be destroyed in the environment. It can only change its form, or become attached to or separated from particles. It may change its form by reacting with oxygen or other molecules present in air, water, or soil, or by the action of bacteria that live in soil or sediment. Arsenic released from power plants and other combustion processes is usually attached to very small particles. Arsenic contained in wind-borne soil is generally found in larger particles. These particles settle to the ground or are washed out of the air by rain. Arsenic that is attached to very small particles may stay in the air for many days and travel long distances. Many common arsenic compounds can dissolve in water. Thus, arsenic can get into lakes, rivers, or underground water by dissolving in rain or snow or through the discharge of industrial wastes. Some of the arsenic will stick to particles in the water or sediment on the bottom of lakes or rivers, and some will be carried along by the water. Ultimately, most arsenic ends up in the soil or sediment. Although some fish and shellfish take in arsenicwhich may build up in tissuesmost of this arsenic is in an organic form called arsenobetaine (commonly called fish arsenic) that is much less harmful. Exposure to arsenic Since arsenic is found naturally in the environment, you will be exposed to some arsenic by eating food, drinking water, or breathing air. Also, children may be exposed to arsenic by eating dirt. You may be exposed by skin contact with soil or water that contains arsenic. Analytical methods used by scientists to determine the levels of arsenic in the environment generally do not determine the specific form of arsenic present. Therefore, we do not always know the form of arsenic a person may be exposed to. Similarly, we often do not know what forms of arsenic are present at hazardous waste sites. Some forms of arsenic may be so tightly attached to particles or embedded in minerals that they are not taken up by plants and animals. The concentration of arsenic in soil varies widely, generally ranging from about 1 to 40 parts of arsenic to a million parts of soil (ppm) with an average level of 3-4 ppm. However, soils in the vicinity of arsenic-rich geological deposits, some mining and smelting sites, or agricultural areas where arsenic pesticides had been applied in the past may contain much higher levels of arsenic. The concentration of arsenic in natural surface and groundwater is generally about 1 part in a billion parts of water (1 ppb), but may exceed 1,000 ppb in mining areas or where arsenic levels in soil are high. Groundwater is far more likely to contain high levels of arsenic than surface water. Surveys of U.S. drinking water indicate that about 80% of water supplies have less than 2 ppb of arsenic, but 2% of supplies exceed 20 ppb of arsenic. Levels of arsenic in food range from about 20 to 140 ppb. However, levels of inorganic arsenic, the form of most concern, are far lower. Levels of arsenic in the air generally range from less than 1 to about 2,000 nanograms (1 nanogram equals a billionth of a gram) of arsenic per cubic meter of air (less than 1-2,000 ng/m 3 ), depending on location, weather conditions, and the level of industrial activity in the area. However, urban areas generally have mean arsenic levels in air ranging from 20 to 30 ng/m 3 . You normally take in small amounts of arsenic in the air you breathe, the water you drink, and the food you eat. Of these, food is usually the largest source of arsenic. Seafood contains the greatest amounts of arsenic, but in fish and shellfish, this is mostly in an organic form of arsenic called arseonbetaine that is much less harmful. Some seaweeds may contain arsenic in inorganic forms that may be more harmful. Children are likely to eat small amounts of dust or dirt each day, so this is another way they may be exposed to arsenic. The total amount of arsenic you take in from these sources is generally about 50 micrograms (1 microgram equals one-millionth of a gram) each day. The level of inorganic arsenic (the form of most concern) you take in from these sources is generally about 3.5 microgram/day. In addition to the normal levels of arsenic in air, water, soil, and food, you could be exposed to higher levels in several ways, such as the following: Some areas of the United States contain unusually high natural levels of arsenic in rock, and this can lead to unusually high levels of arsenic in soil or water. If you live in an area like this, you could take in elevated amounts of arsenic in drinking water. Children may be taking in arsenic because of hand to mouth contact or eating dirt. Some hazardous waste sites contain large quantities of arsenic. If the material is not properly disposed of, it can get into surrounding water, air, or soil. If you live near such a site, you could be exposed to elevated levels of arsenic from these media. If you work in an occupation that involves arsenic production or use (for example, copper or lead smelting, wood treating, pesticide application), you could be exposed to elevated levels of arsenic during your work. If you saw or sand arsenic-treated wood, you could inhale some of the sawdust into your nose or throat. Similarly, if you burn arsenic-treated wood, you could inhale arsenic in the smoke. If you live in a formerly agricultural area where arsenic was used on crops, the soil could contain high levels of arsenic. In the past, several kinds of products used in the home (rat poison, ant poison, weed killer, some types of medicines) had arsenic in them. However, most of these uses of arsenic have ended, so you are not likely to be exposed from home products any longer. Pathways of arsenic to the body If you swallow arsenic in water, soil, or food, most of the arsenic may quickly enter into your body. The amount that enters your body will depend on how much you swallow and the kind of arsenic that you swallow. This is the most likely way for you to be exposed near a waste site. If you breathe air that contains arsenic dusts, many of the dust particles settle onto the lining of the lungs. Most of the arsenic in these particles is then taken up from the lungs into the body. You might be exposed in this way near waste sites where arsenic-contaminated soils are allowed to blow into the air, or if you work with arsenic-containing soil or products. If you get arsenic-contaminated soil or water on your skin, only a small amount will go through your skin into your body, so this is usually not of concern. If you are exposed to arsenic, your liver changes some of this to a less harmful organic form. Both inorganic and organic forms leave your body in your urine. Most of the arsenic will be gone within several days, although some will remain in your body for several months or even longer. Health effects of arsenic Figure 2: Arsenic lesions on feet ( 世界银行图片展 ) Scientists use many tests to protect the public from harmful effects of toxic chemicals and to find ways for treating persons who have been harmed. One way to learn whether a chemical will harm people is to determine how the body absorbs, uses, and releases the chemical. For some chemicals, animal testing may be necessary. Animal testing may also help identify such health effects as cancer or birth defects. Without laboratory animals, scientists would lose a basic method for getting information needed to make wise decisions that protect public health. Scientists have the responsibility to treat research animals with care and compassion. Scientists must comply with strict animal care guidelines because laws today protect the welfare of research animals. Additionally, there are vigorous national and international efforts to develop alternatives to animal testing. The efforts focus on both in vitro and in silico approaches and methods. For example, the National Toxicology Program (NTP) at the National Institute of Environmental Health Sciences (NIEHS) created the NTP Interagency Center for the Evaluation of Alternative Toxicological Methods (NICEATM) in 1998. The role of NICEATM is to serve the needs of high quality, credible science by facilitating development and validationand regulatory and public acceptanceof innovative, revised test methods that reduce, refine, and replace the use of animals in testing while strengthening protection of human health, animal health and welfare, and the environment. In Europe, similar efforts at developing alternatives to animal based testing are taking place under the aegis of the European Centre for the Validation of Alternative Methods (ECVAM). Inorganic arsenic has been recognized as a human poison since ancient times, and large oral doses (above 60,000 ppb in food or water) can result in death. If you swallow lower levels of inorganic arsenic (ranging from about 300 to 30,000 ppb in food or water), you may experience irritation of your stomach and intestines, with symptoms such as stomachache, nausea, vomiting, and diarrhea. Other effects you might experience from swallowing inorganic arsenic include decreased production of red and white blood cells, which may cause fatigue, abnormal heart rhythm, blood-vessel damage resulting in bruising, and impaired nerve function causing a pins and needles sensation in your hands and feet. Perhaps the single-most characteristic effect of long-term oral exposure to inorganic arsenic is a pattern of skin changes. These include a darkening of the skin and the appearance of small corns or warts on the palms, soles, and torso, and are often associated with changes in the blood vessels of the skin (see Figure 2). A small number of the corns may ultimately develop into skin cancer. Swallowing arsenic has also been reported to increase the risk of cancer in the liver, bladder, kidneys, prostate, and lungs. The U.S. Department of Health and Human Services (DHHS) has determined that inorganic arsenic is known to be a human carcinogen. The International Agency for Research on Cancer (IARC) has determined that inorganic arsenic is carcinogenic to humans. The U.S. Environmental Protection Agency (EPA) also has classified inorganic arsenic as a known human carcinogen. If you breathe high levels of inorganic arsenic, then you are likely to experience a sore throat and irritated lungs. You may also develop some of the skin effects mentioned above. The exposure level that produces these effects is uncertain, but it is probably above 100 micrograms of arsenic per cubic meter (g/m 3 ) for a brief exposure. Longer exposure at lower concentrations can lead to skin effects, and also to circulatory and peripheral nervous disorders. There are some data suggesting that inhalation of inorganic arsenic may also interfere with normal fetal development, although this is not certain. An important concern is the ability of inhaled inorganic arsenic to increase the risk of lung cancer. This has been seen mostly in workers exposed to arsenic at smelters, mines, and chemical factories, but also in residents living near smelters and arsenical chemical factories. People who live near waste sites with arsenic may have an increased risk of lung cancer as well. If you have direct skin contact with inorganic arsenic compounds, your skin may become irritated, with some redness and swelling. However, it does not appear that skin contact is likely to lead to any serious internal effects. Despite all of the adverse health effects associated with inorganic arsenic exposure, there is some evidence that the small amounts of arsenic in the normal diet (10-50 ppb) may be beneficial to your health. This phenomenon is known as hormesis. For example, animals fed a diet with unusually low concentrations of arsenic did not gain weight normally. They also became pregnant less frequently than animals fed a diet containing a normal amount of arsenic. Further, the babies of these animals tended to be smaller than normal, and some died at an early age. However, no cases of arsenic deficiency in humans have ever been reported. Almost no information is available on the effects of organic arsenic compounds in humans. Studies in animals show that most simple organic arsenic compounds (such as methyl and dimethyl compounds) are less toxic than the inorganic forms and that some complex organic arsenic compounds are virtually non-toxic. However, high doses can produce some of the same effects. Thus, if you are exposed to high doses of an organic arsenic compound, you might develop nerve injury, stomach irritation, or other effects, but this is not known for certain. Health effects on children This section discusses potential health effects in humans from exposures during the period from conception to maturity at 18 years of age. Children are exposed to arsenic in many of the same ways that adults are. Since arsenic is found in the soil, water, food, and air, children may take in arsenic in the air they breathe, the water they drink, and the food they eat. Since children tend to eat or drink less of a variety of foods and beverages than do adults, ingestion of contaminated food or juice or infant formula made with arsenic-contaminated water may represent a significant source of exposure. In addition, since children often play in the dirt and put their hands in their mouths and sometimes intentionally eat dirt, ingestion of contaminated soil may be a more important source of arsenic exposure for children than for adults. In areas of the United States where natural levels of arsenic in the soil and water are high, or in areas in and around contaminated waste sites, exposure of children to arsenic through ingestion of soil and water may be significant. In addition, contact with adults who are wearing clothes contaminated with arsenic (e.g., with dust from copper- or lead-smelting factories, from wood-treating or pesticide application, or from arsenic-treated wood) could be a source of exposure. Because of the tendency of children to taste things that they find, accidental poisoning from ingestion of pesticides is also a possibility. Thus, although most of the exposure pathways for children are the same as those for adults, children may be at a higher risk of exposure because of normal hand-to-mouth activity. Children who are exposed to arsenic may have many of the same effects as adults, including irritation of the stomach and intestines, blood vessel damage, skin changes, and reduced nerve function. Thus, all health effects observed in adults are of potential concern in children. There is also some evidence that suggests that long-term exposure to arsenic in children may result in lower IQ scores. We do not know if absorption of arsenic from the gut in children differs from adults. There is some information suggesting that children may be less efficient at converting inorganic arsenic to the less harmful organic forms. For this reason, children may be more susceptible to health effects from inorganic arsenic than adults. There is some evidence that inhaled or ingested arsenic can injure pregnant women or their unborn babies, although the studies are not definitive. Studies in animals show that large doses of arsenic that cause illness in pregnant females can also cause low birth weight, fetal malformations, and even fetal death. Arsenic can cross the placenta and has been found in fetal tissues. Arsenic is found at low levels in breast milk. Reducing risk of exposure to arsenic If your doctor finds that you have been exposed to substantial amounts of arsenic, ask whether your children might also have been exposed. Your doctor might need to ask your state health department to investigate. If you use arsenic-treated wood in home projects, personal protection from exposure to arsenic-containing sawdust may be helpful in limiting exposure of family members. These measures may include dust masks, gloves, and protective clothing. Arsenic-treated wood should never be burned in open fires, or in stoves, residential boilers, or fire places, and should not be composted or used as mulch. If you live in an area with a high level of arsenic in the water or soil, substituting cleaner sources of water and limiting contact with soil (for example, through use of a dense groundcover or thick lawn) would reduce family exposure to arsenic. By paying careful attention to dust and dirt control in the home (air filters, frequent cleaning), you can reduce family exposure to contaminated dirt. Some children eat a lot of dirt. You should prevent your children from eating dirt. You should discourage your children from putting objects in their mouths. Make sure they wash their hands frequently and before eating. Discourage your children from putting their hands in their mouths or engaging in other hand-to-mouth activities. Since arsenic may be found in the home as a pesticide, household chemicals containing arsenic should be stored out of reach of young children to prevent accidental poisonings. Always store household chemicals in their original labeled containers; never store household chemicals in containers that children would find attractive to eat or drink from, such as old soda bottles. Keep your Poison Control Center's number by the phone. It is sometimes possible to carry arsenic from work on your clothing, skin, hair, tools, or other objects removed from the workplace. This is particularly likely if you work in the fertilizer, pesticide, glass, or copper/lead smelting industries. You may contaminate your car, home, or other locations outside work where children might be exposed to arsenic. You should know about this possibility if you work with arsenic. Your occupational health and safety officer at work can and should tell you whether chemicals you work with are dangerous and likely to be carried home on your clothes, body, or tools and whether you should be showering and changing clothes before you leave work, storing your street clothes in a separate area of the workplace, or laundering your work clothes at home separately from other clothes. Material safety data sheets (MSDS) for many chemicals used should be found at your place of work, as required by the U.S. Occupational Safety and Health Administration (OSHA) in the U.S. Department of Labor. MSDS information should include chemical names and hazardous ingredients, and important properties, such as fire and explosion data, potential health effects, how you get the chemical(s) in your body, how to properly handle the materials, and what to do in the case of emergencies. Your employer is legally responsible for providing a safe workplace and should freely answer your questions about hazardous chemicals. Your state OSHA-approved occupational safety and health program or OSHA can answer any further questions and help your employer identify and correct problems with hazardous substances. Your state OSHA-approved occupational safety and health program or OSHA will listen to your formal complaints about workplace health hazards and inspect your workplace when necessary. Employees have a right to seek safety and health on the job without fear of punishment. Medical tests for exposure to arsenic Several sensitive and specific tests can measure arsenic in your blood, urine, hair, or fingernailsthrough biomonitoringand these tests are often helpful in determining if you have been exposed to above-average levels of arsenic in the past. These tests are not usually performed in a doctor's office. They require sending the sample to a testing laboratory. Measurement of arsenic in your urine is the most reliable means of detecting arsenic exposures that you experienced within the last several days. Most tests measure the total amount of arsenic present in your urine. This can sometimes be misleading, because the nonharmful forms of arsenic in fish and shellfish can give a high reading even if you have not been exposed to a toxic form of arsenic. For this reason, laboratories sometimes use a more complicated test to separate fish arsenic from other forms. Because most arsenic leaves your body within a few days, analysis of your urine cannot detect if you were exposed to arsenic in the past. Tests of your hair or fingernails can tell if you were exposed to high levels over the past 6-12 months, but these tests are not very useful in detecting low-level exposures. If high levels of arsenic are detected, this shows that you have been exposed, but unless more is known about when you were exposed and for how long, it is usually not possible to predict whether you will have any harmful health effects. Further Reading The Agency for Toxic Substances and Disease Registry Interagency Coordinating Committee on the Validation of Alternative Methods European Centre for the Validation of Alternative Methods Institute for Laboratory Animal Research
1. What is a template? Templates can be described as molecular matrices with the following features and functions: Recognition : A template interacts with complementary binding sites of reaction partners, thus involving selectivity Organisation : A template organizes the reaction partners in space, thus modifying their reactivity Information transfer : Information stored in a template, such as spacial arrangement and recognition pattern, is inherited to the reaction product In a strict sense, templates must be removable from the reaction product, thus distinguishing them from simple reactants. But in supramolecular chemistry, this point is often neglected, since the terms template and templated synthesis are also widely accepted for those reactions in which the template becomes part of the reaction product. 2. How to classify templates? We classify templates according to their topography . Another criterion which is appropriate for a classification is the type of interaction between template and reaction partners (covalent, non-covalent, hydrogen bond, metal-ligand-coordination, hydrophobic effects etc.). In the following images, all components serving as templates are orange colored. 2.1 Convex templates Convex templates have been pioneered early on when crown ethers and other macrocycles were synthesized with the help of a metal cation suitable in size and coordination geometry. This approach is schematically shown in Figure 1. Around the convex surface of cations, more complex species such as rotaxanes or catenanes can be built. One of the examples from the Schalley group is the formation of hexameric pyrogallarene capsules around a templating tris-bipyridine ruthenium(II) dication. Figure 1: Schematic representation of a convex template (orange) around which a macrocycle is formed (blue). Example 1: Catenane synthesis has been done by metal ion templation, utilizing the tetrahedral metal-ligand coordination geometry of copper(I) (C. O. Dietrich-Buchecker, J.-P. Sauvage, J.-P. Kintzinger, Tetrahedron Lett. 1983 , 24, 5095; C. O. Dietrich-Buchecker, J.-P. Sauvage, Chem. Rev. 1987 , 87 , 795). Example 2: The following rotaxane synthesis through a convex anion template utilizes hydrogen bonding between chloride and amide protons and shows that convex templates do not necessarily involve cations (J. A. Wisner, P. D. Beer, M. G. B. Drew, M. R. Sambrook, J. Am. Chem. Soc. 2002 , 124, 12469). 2.2 Concave templates Concave templates organize reaction partners within a cavity, where they usually are bound by non-covalent bonds. Spatial orientation as well as a high local concentration of the partners provoke the desired bond formation (Figure 2). Figure 2: Schematic representation of a concave template (orange) which brings togehter two reacting subunits (blue) inside its cavity. Example 3: A cinnamic acid derivative can be regioselectively photodimerized through a cavitand template, utilizing the hydrophobic effect between cucurbituril and its aromatic guest. Without templation, only the cis- isomer of the monomeric cinnamic acid is obtained (M. Pattabiraman, L. M. Kaanumalle, A. Natarajan, V. Ramamurthy, Langmuir 2006 , 22 , 7605). Example 4: Rotaxane synthesis can be brought about by a macrocyclic tetralactam template, utilizing hydrogen bonding between the amide protons and a stoppering phenolate (G. M. Hbner, J. Glauml;ser, C. Seel, F. Vouml;gtle, Angew. Chem. 1999 , 111 , 395; Angew. Chem. Int. Ed. Engl. 1999 , 38 , 383). Another anion-templated rotaxane synthesis has been developed in our group. The shuttling motion of the wheel along the axle can be controlled by protonation and deprotonation. 2.3 Linear templates An excellent example for a linear template (Figure 3) from nature is single-stranded DNA, along which the complementary strand is synthesized. In artificial systems, linear templates transferring sequence information are rather scarce. A number of examples is known, where the fibers of gels have been used in mineralization experiments. The fiber templates the formation of tunnel-shaped hollow spaces inside the resulting solid after removal of the organic template. Figure 3: Schematic representation of a linear template (orange) combining two building blocks (blue). Example 5: Regioselective photodimerization of trans -1,2-bis(4-pyridyl)ethylene is possible through a linear template, utilizing hydrogen bonding between resorcinol-OH and pyridine-N atoms (L. R. MacGillivray, J. L. Reid, J. A. Ripmeester, J. Am. Chem. Soc. 2000 , 122 , 7817). 2.4 Planar templates: A planar template is usually a surface which binds molecules specifically and enables the self-assembly of these molecules into ordered architectures (Figure 4). One example from our group is the deposition of metallosupramolecular squares on chloride-covered Cu(100) surfaces. A nice example for a planar template is the electropolymerisation of 3,4-ethyldioxythiophene on the liquid crystalline phase serving as template (J. F. Hulvat, S. I. Stupp, Angew. Chem. 2003 , 115 , 802; Angew. Chem. Int. Ed. 2003 , 42 , 778). 3. Summary As shown in some of the examples, templates plays a major role in supramolecular chemistry as well as in nature and opens a pathway to complex molecular architectures - in particular, when combined with self-assembly processes. Understanding template effects is a key to sophisticated supramolecular design. The great variety of possible interactions between templates and reaction partners, encompassing covalent and non-covalent bonds, hydrogen bonds, metal-ligand-coordination and hydrophobic effects etc., makes templates a versatile tool in supramolecular synthesis which is applicable in a broad spectrum of reaction conditions. This paper from Schalley Group homepage: http://userpage.chemie.fu-berlin.de/~schalley/research.html
空间电荷效应space charge effect; 1、所谓的空间电荷效应是指由于电子的分布导致空间存在一个电势的分布.在激光脉冲内这些出射的电子通过逆轫致辐射在激光场中得到能量一方面与气体作用形成气体等离子体 2、 形成了空间电荷层,其电势低于灯丝的电势,称为空间电荷效应.此空间电场会把带负电荷的电子拉回去,抑制电子发射,致使能达到阳极P的电子很小 夫兰克 赫兹实验仪 温度计（ 250 ℃ ） 本世纪初，人类对原子光谱的研究逐步深入，人们发现卢瑟福于 1911 年提出的原子核结构模型与经典电磁理论存在深刻的矛盾。按照经典理论，原子应当是一个不稳定的系统，原子光谱应为连续光谱。但事实上，原子是稳定的，原子光谱是具有一定规律性的分离谱线。为了解决这一矛盾，丹麦物理学家玻尔（ N.Bohr ）根据光谱学研究的成就和普朗克、爱因斯坦的量子论思想，在卢瑟福核式模型基础上，把量子概念应用于原子系统，提出了半经典的氢原子理论，指出原子中存在能级。该模型的预言在氢光谱的观察中取得了显著成功。根据玻尔理论，原子光谱中的每条谱线表示原子从一个能级跃迁到另一个较低能级时产生的辐射。为此， 1922 年玻尔获诺贝尔物理奖。 为了证明原子中电子的运动存在一系列稳定状态 能级， 1914 年，德国物理学家夫兰克 (J.Franck) 和赫兹 (G.Hertz) 巧妙地改进了勒纳用来测量电离电位的实验装置。他们同样采用慢电子（几到几十电子伏）与单原子气体碰撞后电子状态的变化（勒纳观察的是离子）。他们用此装置测定了汞原子的第一激发电位，后又改进电路测出了汞原子的较高激发电位及至电离电位，得到了与原子光谱测量一致的结果，从实验上证实了原子内部能量的分立、不连续性，验证了玻尔理论，为量子理论的创立奠定了实验基础。这两位物理学家于 1925 年获诺贝尔物理奖。 实验原理： 根据玻尔理论的基本假设，原子只能处于一系列稳定状态（简称定态）中，每一稳定状态对应一定的能量值 E n (n=1,2, ) ，这些能量值是彼此分立的，不连续的。原子从一个稳定态过渡到另一个稳定态时，就吸收或放出一定频率的电磁辐射。辐射频率 取决于两定态能量之差 。 原子能量状态的改变可以通过具有一定动能的电子与原子相碰撞进行能量交换来实现。夫兰克 赫兹实验就是通过直接测量出电子碰撞时传递的能量值来证实原子能级存在的。夫兰克赫兹实验的原理图如图 31-1 所示。电子和原子的碰撞是在夫兰克 赫兹实验管中进行的，夫兰克 赫兹管是在抽成真空的电子管中充以某种气体，电子由电阴极发出，阴极 K 与栅极 G 之间的电压 U GK 是使电子加速的；在板极 A 与栅极 G 之间加的是反向电压，它使电子减速，用于探测电子通过 KG 后的状态。这样，电子在 KG 空间被加速时将会与被测气体原子发生碰撞。按玻尔理论，被测气体原子只能接收与其各能级之间能量差相等的能量，而不能接受其他量值的能量。如果电子的动能低于原子第一激发能量，它与气体原子的碰撞将是弹性碰撞，电子几乎不损失能量，因而可能穿过反向电压 U AG 达到板极 A ，被电流计 pA 检出；如果电子加速后具有的动能足够大，足以使气体原子产生激发的话，电子将与气体原子产生非弹性碰撞，把其一部分动能传给原子，使原子从基态跃迁到第一激发态，电子剩下的能量将不足以克服 GA 之间的反向电压，结果将引起板极电流 I A 急剧下降。随着电子继续加速和减速， I A 将随 U GK 周期性的变化， I A -U GK 曲线两峰值之间的电位差就是被测气体原子的第一激发电位。实验观察到的 I A -U GK 曲线如图 31-2 所示。它反映了在 KG 空间中气体原子与电子间进行能量交换的情况。 被测气体可以是惰性气体（如氖、氩气），也可以是汞蒸气。由于常温下汞为液体，因而需要用恒温加热炉，使管中有一定的汞饱和蒸气，其中的原子密度可通过调节加热炉的恒温温度来选择，温度越高管中汞原子密度越大，电子与原子碰撞的机会越多。本实验就是要通过实验测定汞原子的第一激发电位（公认值为 4.9 伏），进而证实原子能级的存在。 原子处于激发态是不稳定的。实验中被慢电子轰击到第一激发态的原子要跳回基态，应有 eU 0 （ U 0 是汞的第一激发电位）电子伏特的能量释放，产生波长为 的光波。 实验中可观察到夫兰克 赫兹管中有淡蓝色的光发出，光谱分析证实了这一波长光波的存在。 假如电子在被加速过程中获得的动能 eU GK 足以补偿原子束缚其电子的势能 eU Z 时，当这样的电子与原子碰撞时，就能从原子中分离出一个电子，使原子变成离子。由于板极电位为负，电子在碰撞后到不了板极，而正的离子才能到达板极形成板极电流 I A 而被电流计检出。通过测量这个电流的变化即可测出该原子的第一电离电位。汞的电离电位是 U Z =10.39V 。
标签: effect
