Search Results for “Oxide”

November 30, 2014

Caffeine

Lu Yu

Caffeinated drink

Caffeine is a naturally occurring chemical found in various seeds, leaves, nuts, and berries. It serves a dual function in plants: as a toxin against unwanted pests, and as an enticement to pollinators, who are stimulated by it. Common sources of caffeine include coffee seeds (beans), tea leaves, kola nuts, yerba mate leaves, and guarana berries. It is extracted from the plant by steeping in water, a process called infusion. Chemically caffeine is an alkaloid, a non-acidic, nitrogen containing compound. A number of alkaloids are produced by flowering plants (e.g. cocaine from coca, nicotine from tobacco, morphine from poppies) to reduce or avoid being eaten by herbivores.

Specifically, caffeine is a xanthine alkaloid, an organic (carbon-based) compound from which many stimulants are derived. It is the world’s most widely consumed psychoactive drug, but unlike many other psychoactive substances, it is legal and unregulated in nearly all parts of the world. Part of the reason caffeine is classified by the FDA as ‘generally recognized as safe’ is that toxic doses, over 10 grams per day for an adult, are much higher than the typically used doses of under 500 milligrams.

November 3, 2014

Near-death Experience

heaven help us by Alex Eben Meyer

Near-death experiences (NDE) are associated with several common phenomena such as feelings of detachment from the body, levitation, serenity, security, warmth, dissolution, and bright light. These sensations are usually reported after an individual has been pronounced clinically dead or has been very close to death. With recent developments in cardiac resuscitation techniques, the number of reported NDEs has increased. According to a 1992 Gallup poll, approximately eight million Americans claim to have had a near-death experience. Popular interest in the topic was initially sparked by psychiatrist Raymond Moody’s 1975 book ‘Life After Life,’ in which he interviewed 150 people who had undergone NDEs.

In 1981, the International Association for Near-Death Studies (IANDS) was founded and the following year began publishing the ‘Journal of Near-Death Studies,’ the only peer-reviewed journal in the field. Research from neuroscience considers the NDE to be a hallucination resulting from one or more of several conditions including cerebral anoxia (insufficient oxygen to the brain), hypercarbia (elevated carbon dioxide in the blood), or damage to the temporal lobes (which are responsible for giving meaning to events). Spiritual thinkers and an parapsychologists have long pointed to NDEs as evidence for an afterlife and mind-body dualism.

October 30, 2014

Maraschino Cherry

Maraschino Cherry

maraska

In the US, a maraschino [mar-uh-skee-noh] cherry is a preserved, sweetened cherry, typically made from light-colored sweet cherries such as the Royal Ann, Rainier, or Gold varieties. In their modern form, the cherries are first preserved in a brine solution usually containing sulfur dioxide and calcium chloride to bleach the fruit, then soaked in a suspension of food coloring (usually Red 40), sugar syrup, and other components.

Maraschino cherries are an ingredient in many cocktails, giving them the nickname: ‘Cocktail cherries.’ As a garnish, they often are used to decorate frozen yogurt, baked ham, cakes, pastry, parfaits, milkshakes, ice cream sundaes, and ice cream sodas. They are frequently included in canned fruit cocktail. They are also used as an accompaniment to sweet paan (an Indian preparation of herbs for chewing), and sometimes, along with some of the maraschino “‘juice,’ put into a glass of Coca-Cola to make an old-fashioned or homemade ‘Cherry Coke.’

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October 29, 2014

Nitrogen Narcosis

narcosis

Nitrogen narcosis [nahr-koh-sis] (also known as ‘raptures of the deep’ and the ‘Martini effect’) is a reversible alteration in consciousness that occurs while diving at depth. It is caused by the anesthetic effect of certain gases at high pressure. The Greek word ‘narcosis’ is derived from ‘narke,’ ‘temporary decline or loss of senses and movement, numbness,’ a term used by Homer and Hippocrates. Narcosis produces a state similar to intoxication caused by drinking alcohol or inhaling nitrous oxide. It can occur during shallow dives, but usually becomes noticeable at depths greater than 30 meters (100 ft).

Except for helium and probably neon, all gases that can be breathed have a narcotic effect, although widely varying in degree. The effect is consistently greater for gases with a higher lipid solubility (the ability to diffuse directly through the fatty part of a cell membrane), and there is good evidence that the two properties are mechanistically related. As depth increases, the mental impairment may become hazardous. Divers can learn to cope with some of the effects of narcosis, but it is impossible to develop a tolerance. Narcosis affects all divers, although susceptibility varies widely from dive to dive, and between individuals.

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May 27, 2014

Phlogiston

Joseph Priestley

The phlogiston [floh-jis-tuhntheory is an obsolete scientific theory that postulated a fire-like element called phlogiston, contained within combustible bodies, that is released during combustion. The name comes from Ancient Greek: ‘phlóx’ (‘flame’). First stated in 1667 by German physician, alchemist, and adventurer, Johann Joachim Becher, the theory attempted to explain burning processes such as combustion and rusting, which are now collectively known as oxidation.

Phlogiston theory permitted chemists to bring clarification of apparently different phenomena into a coherent structure: combustion, metabolism, and configuration of rust. The recognition of the relation between combustion and metabolism was a forerunner of the recognition that the metabolism of living organisms and combustion can be understood in terms of fundamentally related chemical processes.

March 24, 2014

Paperless Office

outbox

paperless office by slug signorino

A paperless office is a work environment in which the use of paper is eliminated or greatly reduced by converting documents into digital form. Proponents claim that ‘going paperless’ can save money, boost productivity, save space, make documentation and information sharing easier, keep personal information more secure, and help the environment. The concept can be extended to communications outside the office as well.

Traditional offices have paper-based filing systems, which may include filing cabinets, folders, shelves, microfiche systems, and drawing cabinets, all of which require maintenance, equipment, considerable space, and are resource-intensive. In contrast, a paperless office could simply have a desk, chair, and computer (with a modest amount of local or network storage), and all of the information would be stored in digital form. Speech recognition and speech synthesis could also be used to facilitate the storage of information digitally.

June 12, 2013

False Balance

false balance

Power Balance

Today, false balance is used to describe a perceived or real media bias, where journalists present an issue as being more balanced between opposing viewpoints than the evidence actually supports. Journalists may present evidence and arguments out of proportion to the actual evidence for each side, or may even actually suppress information which would establish one side’s claims as baseless. False balance is also often found in political reports, company press releases, and general information from organizations with special interest groups in promoting their respective agendas.

An example of issues sometimes handled with false balance are pseudoscience, as when a national nightly news program in the US gave coverage to a backyard inventor who claimed to have invented a perpetual motion machine; the program presented scientific authorities to explain why such a device was impossible, but since they gave equal time to the claims of the inventor, it may have created a false impression with audiences that his claims were credible, although they were not. ‘Objective coverage’ of lynching in the 1890s by US journalists failed, ‘to recognize a truth, that African-Americans were being terrorized across the nation.’

June 4, 2013

Nathan Myhrvold

modernist cuisine

nathan myhrvold

Nathan Myhrvold (b. 1959), formerly Chief Technology Officer at Microsoft, is co-founder and 40% owner of Intellectual Ventures, a patent portfolio holding company.

Myhrvold, usually with coinventors, holds 17 U.S. patents assigned to Microsoft and has applied for more than 500 patents. In addition, Myhrvold and coinventors hold 115 U.S. patents assigned mostly to The Invention Science Fund I, LLC.

April 22, 2013

Rust

rust

Rust is a type of corrosion (the breakdown of materials due to reactions with their surroundings). Normally, when a material corrodes it becomes weaker, however some forms of high temperature corrosion can lead to the formation of protective compacted oxide layer glazes. Iron corrosion is called rusting. When exposed to air or water for a long time, iron slowly decomposes into other chemicals, because of a reaction with oxygen molecules (air and water contain oxygen). Many other metals undergo equivalent corrosion, but the resulting oxides are not commonly called rust.

Almost all metals rust, but they can be protected with paint. Alloys such as stainless steel, rust much slower than simple metals like pure iron. When a piece of metal rusts, it becomes a different color (for example, iron becomes red or brown), and the metal eventually decays (iron cannot be used or reused once it rusts). Some metals, such as aluminium, titanium, and stainless steel form a very thin coating of corrosion on the metal, which isolates the rest of the metal from environmental oxygen. This is why aluminium keeps its shine. It also makes aluminium seem very unreactive, even though it can react with water.

March 9, 2013

Shaken, not stirred

shaken not stirred

Shaken, not stirred‘ is a catchphrase of Ian Fleming’s fictional British Secret Service agent James Bond, and his preference for how he wished his martini prepared. The phrase first appears in the novel ‘Diamonds Are Forever’ (1956), though Bond does not actually say the line until ‘Dr. No’ (1958) but says it ‘shaken and not stirred’ instead of ‘shaken, not stirred.’ It was first uttered in the films by Sean Connery in Goldfinger in 1964 (though the villain Dr. Julius No offers this drink and utters those words in the first film, Dr. No, in 1962).

It was used in numerous Bond films thereafter with the notable exceptions of ‘You Only Live Twice,’ in which the drink is offered stirred, not shaken (Bond, ever the gentleman, ignores his host’s gaffe, telling him the drink is perfect), and ‘Casino Royale,’ in which Bond, after losing millions of dollars in a game of poker, is asked if he wants his martini shaken or stirred, and snaps, ‘Do I look like I give a damn?’

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February 13, 2013

Head Shop

psychedelic shop

A head shop is a retail outlet specializing in drug paraphernalia, as well as counterculture art, magazines, music, clothing, and home decor. 

January 31, 2013

Free-radical Theory of Aging

free radicals

antioxidant

The free radical theory of aging states that organisms age because cells accumulate free radical damage over time. A free radical is a molecule with an unpaired electron. The molecule is reactive and seeks another electron to pair. This initiates an uncontrolled chain reaction that can damage the natural function of the living cell, causing various diseases. While a few free radicals such as melanin are not chemically reactive, most biologically-relevant free radicals are highly reactive. For most biological structures, free radical damage is closely associated with oxidative damage. Antioxidants are reducing agents, they limit oxidative damage to biological structures by donating an electron to free radicals. Biogerontologist Denham Harman first proposed the free radical theory of aging in the 1950s, and in the 1970s extended the idea to implicate mitochondrial production of reactive oxygen species.

In some model organisms, such as yeast and Drosophila (fruit fly), there is evidence that reducing oxidative damage can extend lifespan. In mice, interventions that enhance oxidative damage generally shorten lifespan. However, in roundworms, blocking the production of the naturally occurring antioxidant superoxide dismutase has recently been shown to increase lifespan. Whether reducing oxidative damage below normal levels is sufficient to extend lifespan remains an open and controversial question.

January 22, 2013

Oxidation

redox

Oxidation [ok-si-dey-shuhn] is any chemical reaction that involves a loss of electrons. For example, when iron reacts with oxygen it forms a chemical called rust: the iron is oxidized (loses electrons) and the oxygen is reduced (gains electrons). A reduction reaction always comes together with its opposite, the oxidation reaction, and together are called ‘redox’ (reduction and oxidation). Although oxidation reactions are commonly associated with the formation of oxides from oxygen molecules, these are only specific examples of a more general concept of reactions involving electron transfer. The word ‘oxidation’ originally implied reaction with oxygen to form an oxide, since (di)oxygen was historically the first recognized oxidizing agent. Later, the term was expanded to encompass oxygen-like substances that accomplished parallel chemical reactions. Ultimately, the meaning was generalized to include all processes involving loss of electrons. The word ‘reduction’ originally referred to the loss in weight upon heating a metallic ore such as a metal oxide to extract the metal. In other words, ore was ‘reduced’ to metal. Antoine Lavoisier (1743-1794) showed that this loss of weight was due to the loss of oxygen as a gas. Later, scientists realized that the metal atom gains electrons in this process. The meaning of reduction then became generalized to include all processes involving gain of electrons. Even though ‘reduction’ seems counter-intuitive when speaking of the gain of electrons, it might help to think of reduction as the loss of oxygen, which was its historical meaning.

Many important biological processes involve redox reactions. Cellular respiration, for instance, is the oxidation of glucose to carbon dioxide and the reduction of oxygen to water. Photosynthesis is the reaction in reverse (the reduction of carbon dioxide into sugars and the oxidation of water into molecular oxygen). Free radical reactions are redox reactions that occur as a part of homeostasis and killing microorganisms, where an electron detaches from a molecule and then reattaches almost instantaneously. Free radicals (molecules with an unpaired electron) are a part of redox molecules and can become harmful to the human body if they do not reattach to the redox molecule or an antioxidant (a molecule that inhibits oxidation reactions by donating an electron to the free radical). Unsatisfied free radicals can spur the mutation of cells they encounter and are thus causes of cancer.

January 16, 2013

Common Misconceptions

swallow gum

Common misconceptions are widely held, erroneous ideas and beliefs about notable topics which have been reported by reliable sources. Each has been discussed in published literature, as has its topic area and the facts concerning it. For example, in ancient Rome, the architectural feature called a ‘vomitorium’ was the entranceway through which crowds entered and exited a stadium, not a special room used for purging food during meals. Vomiting was not a regular part of Roman dining customs.

Also, Nero did not ‘fiddle’ during the Great Fire of Rome (violins had not yet been invented, nor was he playing the lyre). In fact, according to Roman historian Tacitus, upon hearing news of the fire, Nero rushed back to Rome to organize a relief effort, which he paid for from his own funds, and he also opened his palaces to provide shelter for the homeless, arranging for food supplies to be delivered in order to prevent starvation among the survivors. Finally, he made a new urban development plan that attempted to make it more difficult for fires to spread.

November 14, 2012

Homeopathy

Homeopathy [hoh-mee-op-uh-theeis a system of alternative medicine originated in 1796 by German physicist Samuel Hahnemann, based on the doctrine of ‘similia similibus curentur’ (‘like cures like’), according to which a substance that causes the symptoms of a disease in healthy people will cure that disease in sick people. Scientific research has found homeopathic remedies ineffective and their postulated mechanisms of action implausible. Within the medical community homeopathy is generally considered quackery. Homeopathic remedies are prepared by repeatedly diluting a chosen substance in alcohol or distilled water, followed by forceful striking on an elastic body, called ‘succussion.’ Each dilution followed by succussion is said to increase the remedy’s potency. Dilution usually continues well past the point where none of the original substance remains. Homeopaths select remedies by consulting reference books known as ‘repertories,’ considering the totality of the patient’s symptoms as well as the patient’s personal traits, physical and psychological state, and life history.

The low concentrations of homeopathic remedies, often lacking even a single molecule of the diluted substance, lead to an objection that has dogged homeopathy since the 19th century: how, then, can the substance have any effect? Modern advocates of homeopathy have suggested that ‘water has a memory’—that during mixing and succussion, the substance leaves an enduring effect on the water, perhaps a ‘vibration,’ and this produces an effect on the patient. However, nothing like water memory has ever been found in chemistry or physics. Pharmacological research has found, contrary to homeopathy, that stronger effects of an active ingredient come from higher doses, not lower doses. Homeopathic remedies have been the subject of numerous clinical trials, which test the possibility that they may be effective through some mechanism unknown to science. Taken together, these trials showed no effect beyond placebo. The proposed mechanisms for homeopathy are precluded by the laws of physics from having any effect. 

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