1.
Skull and crossbones (poison)
–
A skull and crossbones is a symbol consisting of a human skull and two long bones crossed together under the skull. The design originates in the Late Middle Ages as a symbol of death, in modern contexts, it is generally used as a hazard symbol that warns of danger, usually in regard to poisonous substances, such as deadly chemicals. Unicode uses U+2620 ☠ SKULL AND CROSSBONES for the symbol, the symbol originates with the medieval Danse Macabre symbolism. By the 15th century, the symbol had developed into its familiar form and it came to be used specifically to mark the entrances of Spanish cemeteries, and has been used to mark poison and other dangerous liquids and powders since the 19th century. The skull and bones are used in military insignia, e. g. in coats of arms of some military regiments. In 1829, New York State required the labeling of all containers of poisonous substances, the skull and crossbones symbol appears to have been used for that purpose since the 1850s. Previously a variety of motifs had been used, including the Danish + + +, for this reason, in the United States there has been a proposal to replace the skull and crossbones by the Mr. Yuk symbol. This means that the name and graphic image cannot be used without a license from the owner—unlike the Skull and crossbones, ossuary Danse Macabre Hazard symbol Human skull symbolism Jolly Roger Mr. Yuk Totenkopf
Skull and crossbones (poison)
–
A skull and crossbones warning about dangerous voltage in Mumbai, India
Skull and crossbones (poison)
–
The skull-and-crossbone symbol in origin depicts the typical arrangement of skulls and
humeri in
ossuaries, as in the depicted example from
Sedlec (Czech Republic).
Skull and crossbones (poison)
–
An early 17th century "plague panel" from
Augsburg.
2.
Chemical substance
–
A chemical substance is a form of matter that has constant chemical composition and characteristic properties. It cannot be separated into components by physical methods, i. e. without breaking chemical bonds. Chemical substances can be chemical elements, chemical compounds, ions or alloys, Chemical substances are often called pure to set them apart from mixtures. A common example of a substance is pure water, it has the same properties. Other chemical substances commonly encountered in pure form are diamond, gold, table salt, however, in practice, no substance is entirely pure, and chemical purity is specified according to the intended use of the chemical. Chemical substances exist as solids, liquids, gases, or plasma, Chemical substances may be combined or converted to others by means of chemical reactions. Forms of energy, such as light and heat, are not matter, a chemical substance may well be defined as any material with a definite chemical composition in an introductory general chemistry textbook. According to this definition a chemical substance can either be a chemical element or a pure chemical compound. But, there are exceptions to this definition, a substance can also be defined as a form of matter that has both definite composition and distinct properties. The chemical substance index published by CAS also includes several alloys of uncertain composition, in geology, substances of uniform composition are called minerals, while physical mixtures of several minerals are defined as rocks. Many minerals, however, mutually dissolve into solid solutions, such that a rock is a uniform substance despite being a mixture in stoichiometric terms. Feldspars are an example, anorthoclase is an alkali aluminium silicate. In law, chemical substances may include both pure substances and mixtures with a composition or manufacturing process. For example, the EU regulation REACH defines monoconstituent substances, multiconstituent substances and substances of unknown or variable composition, the latter two consist of multiple chemical substances, however, their identity can be established either by direct chemical analysis or reference to a single manufacturing process. For example, charcoal is a complex, partially polymeric mixture that can be defined by its manufacturing process. Therefore, although the chemical identity is unknown, identification can be made to a sufficient accuracy. The CAS index also includes mixtures, polymers almost always appear as mixtures of molecules of multiple molar masses, each of which could be considered a separate chemical substance. However, the polymer may be defined by a precursor or reaction
Chemical substance
–
Steam and liquid water are two different forms of the same chemical substance, water.
Chemical substance
–
Colors of a single chemical (
Nile red) in different solvents, under visible and UV light, showing how the chemical interacts dynamically with its solvent environment.
Chemical substance
–
Native sulfur crystals. Sulfur occurs naturally as elemental sulfur, in
sulfide and
sulfate minerals and in
hydrogen sulfide.
Chemical substance
–
Potassium ferricyanide is a compound of potassium, iron, carbon and nitrogen; although it contains cyanide anions, it does not release them and is nontoxic.
3.
Organism
–
In biology, an organism is any contiguous living system, such as an animal, plant, fungus, protist, archaeon, or bacterium. All known types of organisms are capable of some degree of response to stimuli, reproduction, growth and development and homeostasis. An organism consists of one or more cells, when it has one cell it is known as an organism. Most unicellular organisms are of microscopic scale and are thus described as microorganisms. Humans are multicellular organisms composed of trillions of cells grouped into specialized tissues. An organism may be either a prokaryote or a eukaryote, prokaryotes are represented by two separate domains—bacteria and archaea. Eukaryotic organisms are characterized by the presence of a cell nucleus. Fungi, animals and plants are examples of kingdoms of organisms within the eukaryotes, estimates on the number of Earths current species range from 10 million to 14 million, of which only about 1.2 million have been documented. More than 99% of all species, amounting to five billion species. In 2016, a set of 355 genes from the last universal ancestor of all living organisms living was identified. The term organism first appeared in the English language in 1703 and it is directly related to the term organization. There is a tradition of defining organisms as self-organizing beings. An organism may be defined as an assembly of molecules functioning as a more or less stable whole that exhibits the properties of life. Dictionary definitions can be broad, using such as any living structure, such as a plant, animal, fungus or bacterium, capable of growth. Many definitions exclude viruses and possible man-made non-organic life forms, as viruses are dependent on the machinery of a host cell for reproduction. A superorganism is an organism consisting of individuals working together as a single functional or social unit. There has been controversy about the best way to define the organism, several contributions are responses to the suggestion that the category of organism may well not be adequate in biology. Viruses are not typically considered to be organisms because they are incapable of autonomous reproduction and this controversy is problematic because some cellular organisms are also incapable of independent survival and live as obligatory intracellular parasites
Organism
–
These
Escherichia coli cells provide an example of a
prokaryotic microorganism.
Organism
–
A
polypore mushroom has a
parasitic relationship with its
host.
Organism
–
An
ericoid mycorrhizal fungus
Organism
4.
Animal
–
Animals are multicellular, eukaryotic organisms of the kingdom Animalia. The animal kingdom emerged as a clade within Apoikozoa as the group to the choanoflagellates. Animals are motile, meaning they can move spontaneously and independently at some point in their lives and their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later in their lives. All animals are heterotrophs, they must ingest other organisms or their products for sustenance, most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago. Animals can be divided broadly into vertebrates and invertebrates, vertebrates have a backbone or spine, and amount to less than five percent of all described animal species. They include fish, amphibians, reptiles, birds and mammals, the remaining animals are the invertebrates, which lack a backbone. These include molluscs, arthropods, annelids, nematodes, flatworms, cnidarians, ctenophores, the study of animals is called zoology. The word animal comes from the Latin animalis, meaning having breath, the biological definition of the word refers to all members of the kingdom Animalia, encompassing creatures as diverse as sponges, jellyfish, insects, and humans. Aristotle divided the world between animals and plants, and this was followed by Carl Linnaeus, in the first hierarchical classification. In Linnaeuss original scheme, the animals were one of three kingdoms, divided into the classes of Vermes, Insecta, Pisces, Amphibia, Aves, and Mammalia. Since then the last four have all been subsumed into a single phylum, in 1874, Ernst Haeckel divided the animal kingdom into two subkingdoms, Metazoa and Protozoa. The protozoa were later moved to the kingdom Protista, leaving only the metazoa, thus Metazoa is now considered a synonym of Animalia. Animals have several characteristics that set apart from other living things. Animals are eukaryotic and multicellular, which separates them from bacteria and they are heterotrophic, generally digesting food in an internal chamber, which separates them from plants and algae. They are also distinguished from plants, algae, and fungi by lacking cell walls. All animals are motile, if only at life stages. In most animals, embryos pass through a stage, which is a characteristic exclusive to animals. With a few exceptions, most notably the sponges and Placozoa and these include muscles, which are able to contract and control locomotion, and nerve tissues, which send and process signals
Animal
–
Carl Linnaeus, known as the father of modern
taxonomy
Animal
–
Had'n
Animal
–
The use of
love darts by the land snail
Monachoides vicinus is a form of
sexual selection
Animal
–
A
newt lung cell stained with
fluorescent dyes undergoing the early
anaphase stage of
mitosis
5.
Bacteria
–
Bacteria constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a number of shapes, ranging from spheres to rods, Bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, Bacteria also live in symbiotic and parasitic relationships with plants and animals. Most bacteria have not been characterised, and only half of the bacterial phyla have species that can be grown in the laboratory. The study of bacteria is known as bacteriology, a branch of microbiology, There are typically 40 million bacterial cells in a gram of soil and a million bacterial cells in a millilitre of fresh water. There are approximately 5×1030 bacteria on Earth, forming a biomass which exceeds that of all plants, Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of bodies and bacteria are responsible for the putrefaction stage in this process. In March 2013, data reported by researchers in October 2012, was published and it was suggested that bacteria thrive in the Mariana Trench, which with a depth of up to 11 kilometres is the deepest known part of the oceans. Other researchers reported related studies that microbes thrive inside rocks up to 580 metres below the sea floor under 2.6 kilometres of ocean off the coast of the northwestern United States. According to one of the researchers, You can find microbes everywhere—theyre extremely adaptable to conditions, the vast majority of the bacteria in the body are rendered harmless by the protective effects of the immune system, though many are beneficial particularly in the gut flora. However several species of bacteria are pathogenic and cause diseases, including cholera, syphilis, anthrax, leprosy. The most common fatal diseases are respiratory infections, with tuberculosis alone killing about 2 million people per year. In developed countries, antibiotics are used to treat infections and are also used in farming, making antibiotic resistance a growing problem. Once regarded as constituting the class Schizomycetes, bacteria are now classified as prokaryotes. Unlike cells of animals and other eukaryotes, bacterial cells do not contain a nucleus and these evolutionary domains are called Bacteria and Archaea. The ancestors of modern bacteria were unicellular microorganisms that were the first forms of life to appear on Earth, for about 3 billion years, most organisms were microscopic, and bacteria and archaea were the dominant forms of life. In 2008, fossils of macroorganisms were discovered and named as the Francevillian biota, however, gene sequences can be used to reconstruct the bacterial phylogeny, and these studies indicate that bacteria diverged first from the archaeal/eukaryotic lineage. Bacteria were also involved in the second great evolutionary divergence, that of the archaea, here, eukaryotes resulted from the entering of ancient bacteria into endosymbiotic associations with the ancestors of eukaryotic cells, which were themselves possibly related to the Archaea
Bacteria
–
Had'n
Bacteria
Bacteria
–
A
biofilm of thermophilic bacteria in the outflow of
Mickey Hot Springs,
Oregon, approximately 20 mm thick.
Bacteria
–
Helicobacter pylori electron micrograph, showing multiple flagella on the cell surface
6.
Plant
–
Plants are mainly multicellular, predominantly photosynthetic eukaryotes of the kingdom Plantae. The term is generally limited to the green plants, which form an unranked clade Viridiplantae. This includes the plants, conifers and other gymnosperms, ferns, clubmosses, hornworts, liverworts, mosses and the green algae. Green plants have cell walls containing cellulose and obtain most of their energy from sunlight via photosynthesis by primary chloroplasts and their chloroplasts contain chlorophylls a and b, which gives them their green color. Some plants are parasitic and have lost the ability to produce amounts of chlorophyll or to photosynthesize. Plants are characterized by sexual reproduction and alternation of generations, although reproduction is also common. There are about 300–315 thousand species of plants, of which the great majority, green plants provide most of the worlds molecular oxygen and are the basis of most of Earths ecologies, especially on land. Plants that produce grains, fruits and vegetables form humankinds basic foodstuffs, Plants play many roles in culture. They are used as ornaments and, until recently and in variety, they have served as the source of most medicines. The scientific study of plants is known as botany, a branch of biology, Plants are one of the two groups into which all living things were traditionally divided, the other is animals. The division goes back at least as far as Aristotle, who distinguished between plants, which generally do not move, and animals, which often are mobile to catch their food. Much later, when Linnaeus created the basis of the system of scientific classification. Since then, it has become clear that the plant kingdom as originally defined included several unrelated groups, however, these organisms are still often considered plants, particularly in popular contexts. When the name Plantae or plant is applied to a group of organisms or taxon. The evolutionary history of plants is not yet settled. Those which have been called plants are in bold, the way in which the groups of green algae are combined and named varies considerably between authors. Algae comprise several different groups of organisms which produce energy through photosynthesis, most conspicuous among the algae are the seaweeds, multicellular algae that may roughly resemble land plants, but are classified among the brown, red and green algae. Each of these groups also includes various microscopic and single-celled organisms
Plant
–
Green algae from
Ernst Haeckel 's
Kunstformen der Natur, 1904.
Plant
–
Had'n
Plant
–
Dicksonia antarctica, a species of
tree fern
Plant
–
A petrified log in
Petrified Forest National Park.
7.
Cell (biology)
–
The cell is the basic structural, functional, and biological unit of all known living organisms. A cell is the smallest unit of life that can replicate independently, the study of cells is called cell biology. Cells consist of cytoplasm enclosed within a membrane, which contains many such as proteins. Organisms can be classified as unicellular or multicellular, while the number of cells in plants and animals varies from species to species, humans contain more than 10 trillion cells. Most plant and animal cells are only under a microscope. The cell was discovered by Robert Hooke in 1665, who named the unit for its resemblance to cells inhabited by Christian monks in a monastery. Cells emerged on Earth at least 3.5 billion years ago, Cells are of two types, eukaryotic, which contain a nucleus, and prokaryotic, which do not. Prokaryotes are single-celled organisms, while eukaryotes can be either single-celled or multicellular, prokaryotic cells were the first form of life on Earth, characterised by having vital biological processes including cell signaling and being self-sustaining. They are simpler and smaller than eukaryotic cells, and lack membrane-bound organelles such as the nucleus, prokaryotes include two of the domains of life, bacteria and archaea. The DNA of a prokaryotic cell consists of a chromosome that is in direct contact with the cytoplasm. The nuclear region in the cytoplasm is called the nucleoid, most prokaryotes are the smallest of all organisms ranging from 0.5 to 2.0 µm in diameter. Though most prokaryotes have both a cell membrane and a wall, there are exceptions such as Mycoplasma and Thermoplasma which only possess the cell membrane layer. The envelope gives rigidity to the cell and separates the interior of the cell from its environment, the cell wall consists of peptidoglycan in bacteria, and acts as an additional barrier against exterior forces. It also prevents the cell from expanding and bursting from osmotic pressure due to a hypotonic environment, some eukaryotic cells also have a cell wall. Inside the cell is the region that contains the genome, ribosomes. The genetic material is found in the cytoplasm. Prokaryotes can carry extrachromosomal DNA elements called plasmids, which are usually circular, linear bacterial plasmids have been identified in several species of spirochete bacteria, including members of the genus Borrelia notably Borrelia burgdorferi, which causes Lyme disease. Though not forming a nucleus, the DNA is condensed in a nucleoid, plasmids encode additional genes, such as antibiotic resistance genes
Cell (biology)
–
Onion (
Allium) cells in different phases of the cell cycle
Cell (biology)
–
Structure of an animal cell
Cell (biology)
–
A fluorescent image of an endothelial cell. Nuclei are stained blue,
mitochondria are stained red, and microfilaments are stained green.
Cell (biology)
–
Human cancer cells with nuclei (specifically the DNA) stained blue. The central and rightmost cell are in
interphase, so the entire nuclei are labeled. The cell on the left is going through
mitosis and its DNA has condensed.
8.
Metaphor
–
A metaphor is a figure of speech that refers, for rhetorical effect, to one thing by mentioning another thing. It may provide clarity or identify hidden similarities between two ideas, antithesis, hyperbole, metonymy and simile are all types of metaphor. The Philosophy of Rhetoric by rhetorician I. A. Richards describes a metaphor as having two parts, the tenor and the vehicle, the tenor is the subject to which attributes are ascribed. The vehicle is the object whose attributes are borrowed, other writers employ the general terms ground and figure to denote the tenor and the vehicle. Cognitive linguistics uses the target and source, respectively. Metaphors are most frequently compared with similes, a simile is a specific type of metaphor that uses the words like or as in comparing two objects, whereas what is commonly referred to as a metaphor states that A is B or substitutes B for A. What is usually referred to as a metaphor asserts the two objects in the comparison are identical on the point of comparison, a simile merely asserts a similarity, for this reason a common-type metaphor is generally considered more forceful than a simile. The metaphor category also contains these types, Allegory, An extended metaphor wherein a story illustrates an important attribute of the subject. Antithesis, A rhetorical contrast of ideas by means of parallel arrangements of words, clauses, or sentences Catachresis, A mixed metaphor used by design and accident. Hyperbole, Excessive exaggeration to illustrate a point Metonymy, A figure of speech using the name of one thing in reference to a different thing of which the first is associated, example, in lands belonging to the crown the word crown is metonymy for ruler or monarch. Parable, An extended metaphor narrated as an anecdote illustrating and teaching such as in Aesops fables, pun, Similar to a metaphor, a pun alludes to another term. However, the difference is that a pun is a frivolous allusion between two different things whereas a metaphor is a purposeful allusion between two different things. Metaphor, like other types of analogy, can usefully be distinguished from metonymy as one of two modes of thought. Thus, a metaphor creates new links between otherwise distinct conceptual domains, whereas a metonymy relies on the links within them. A dead metaphor is one in which the sense of an image has become absent. Examples, to grasp a concept and to gather what youve understood use physical action as a metaphor for understanding, the audience does not need to visualize the action, dead metaphors normally go unnoticed. Some people distinguish between a dead metaphor and a cliché, others use dead metaphor to denote both. A mixed metaphor is one that leaps from one identification to a second identification inconsistent with the first, e. g. Checkmate
Metaphor
–
A
political cartoon from an 1894
Puck magazine by illustrator S.D. Ehrhart, shows a farm woman labeled "Democratic Party" sheltering from a tornado of political change.
Metaphor
–
A metaphorical visualization of the word
anger.
Metaphor
–
Tombstone of a
Jewish woman depicting broken candles, a visual metaphor of the end of life.
9.
Family
–
Family is the second album released by May J. and her first under the label Rhythm Zone. No singles were released form the album and it entered the daily Oricon chart at #5 and climbed to #3. DJ Kaori, Diggy-Mo, Clench and Blistah もし君と. with Kimaguren 旅立つ君に Family, Clench and Blistah Unity Crescent Moon, Daishi Dance Remix もし君と… with キマグレン, Music Video Garden feat. DJ Kaori, Diggy-Mo’, クレンチ＆ブリスタ, Music Video 旅立つ君に, Music Video Making of music videos and private movie in Okinawa
Family
10.
Poison
–
In biology, poisons are substances that cause disturbances in organisms, usually by chemical reaction or other activity on the molecular scale, when an organism absorbs a sufficient quantity. The fields of medicine and zoology often distinguish a poison from a toxin, toxins are poisons produced by organisms in nature, and venoms are toxins injected by a bite or sting. The difference between venom and other poisons is the delivery method, industry, agriculture, and other sectors use poisons for reasons other than their toxicity. Pesticides are one group of substances whose toxicity to various insects, in 2013,3.3 million cases of unintentional poisonings occurred. This resulted in 98,000 deaths worldwide, down from 120,000 deaths in 1990, the use of poison as an adjective dates from the 1520s. Using the word poison with plant names dates from the 18th century, the term poison ivy, for example, was first used in 1784 and the term poison oak was first used in 1743. The term poison gas was first used in 1915, paracelsus, the father of toxicology, once wrote, Everything is poison, there is poison in everything. Only the dose makes a thing not a poison, the term poison is also used in a figurative sense, His brothers presence poisoned the atmosphere at the party. The law defines poison more strictly, substances not legally required to carry the label poison can also cause a medical condition of poisoning. Some poisons are also toxins, which is any poison produced by animals, vegetables or bacterium, such as the proteins that cause tetanus. A distinction between the two terms is not always observed, even among scientists, the derivative forms toxic and poisonous are synonymous. Animal poisons delivered subcutaneously are also called venom, in normal usage, a poisonous organism is one that is harmful to consume, but a venomous organism uses venom to kill its prey or defend itself while still alive. A single organism can be poisonous and venomous, but that is rare. Human antimicrobial peptides which are toxic to viruses, fungi, bacteria, in nuclear physics, a poison is a substance that obstructs or inhibits a nuclear reaction. For an example, see nuclear poison, environmentally hazardous substances are not necessarily poisons, and vice versa. Biologically speaking, any substance, if given in large amounts, is poisonous. For instance, several kilograms worth of water would constitute a lethal dose, many substances used as medications—such as fentanyl—have an LD50 only one order of magnitude greater than the ED50. An alternative classification distinguishes between lethal substances that provide a value and those that do not
Poison
–
"Poisoning of Queen
Bona " by
Jan Matejko.
Poison
–
The GHS pictogram for poisonous substances. The
skull and crossbones has long been a standard symbol for poison.
11.
Toxicology
–
Toxicology is a branch of biology, chemistry, and medicine concerned with the study of the adverse effects of chemicals on living organisms. It also studies the effects of chemical, biological and physical agents in biological systems that establishes the extent of damage in living organisms. The relationship between dose and its effects on the organism is of high significance in toxicology. Factors that influence chemical toxicity include the dosage, the route of exposure, dioscorides, a Greek physician in the court of the Roman emperor Nero, made the first attempt to classify plants according to their toxic and therapeutic effect. Ibn Wahshiyya wrote the Book on Poisons in the 9th or 10th century and this was followed up in 1360 by Khagendra Mani Darpana. Mathieu Orfila is considered the father of toxicology, having given the subject its first formal treatment in 1813 in his Traité des poisons. In 1850, Jean Stas became the first person to isolate plant poisons from human tissue. Theophrastus Phillipus Auroleus Bombastus von Hohenheim is also considered the father of toxicology and this is often condensed to, The dose makes the poison or in Latin Sola dosis facit venenum. The goal of toxicity assessment is to identify effects of a substance. Adverse effects depend on two factors, i) routes of exposure and ii) dose. To explore dose, substances are tested in both acute and chronic models, generally, different sets of experiments are conducted to determine whether a substance causes cancer and to examine other forms of toxicity. Factors that influence chemical toxicity, Dosage Both large single exposures, the classic experimental tool of toxicology is testing on non-human animals. As of 2014, such animal testing provides information that is not available by other means about how substances function in a living organism, while testing in animal models remains as a method of estimating human effects, there are both ethical and technical concerns with animal testing. This work requires expert knowledge in molecular modeling and statistics together with expert judgment in chemistry, pivotal events in science include the discovery of penicillin, the elucidation of the DNA double helix, and the development of computers. Toxicity testing is approaching such a scientific pivot point. It is poised to take advantage of the revolutions in biology and biotechnology, as of 2010 that vision was still unrealized. As of 2014 that vision was still unrealized, in some cases shifts away from animal studies has been mandated by law or regulation, the European Union prohibited use of animal testing for cosmetics in 2013. Most chemicals display a dose response curve – at a low dose. A few chemicals have no well-defined safe level of exposure and these are treated with special care
Toxicology
–
Lithograph of Mathieu Orfila
12.
Water
–
Water is a transparent and nearly colorless chemical substance that is the main constituent of Earths streams, lakes, and oceans, and the fluids of most living organisms. Its chemical formula is H2O, meaning that its molecule contains one oxygen, Water strictly refers to the liquid state of that substance, that prevails at standard ambient temperature and pressure, but it often refers also to its solid state or its gaseous state. It also occurs in nature as snow, glaciers, ice packs and icebergs, clouds, fog, dew, aquifers, Water covers 71% of the Earths surface. It is vital for all forms of life. Only 2. 5% of this water is freshwater, and 98. 8% of that water is in ice and groundwater. Less than 0. 3% of all freshwater is in rivers, lakes, and the atmosphere, a greater quantity of water is found in the earths interior. Water on Earth moves continually through the cycle of evaporation and transpiration, condensation, precipitation. Evaporation and transpiration contribute to the precipitation over land, large amounts of water are also chemically combined or adsorbed in hydrated minerals. Safe drinking water is essential to humans and other even though it provides no calories or organic nutrients. There is a correlation between access to safe water and gross domestic product per capita. However, some observers have estimated that by 2025 more than half of the population will be facing water-based vulnerability. A report, issued in November 2009, suggests that by 2030, in developing regions of the world. Water plays an important role in the world economy, approximately 70% of the freshwater used by humans goes to agriculture. Fishing in salt and fresh water bodies is a source of food for many parts of the world. Much of long-distance trade of commodities and manufactured products is transported by boats through seas, rivers, lakes, large quantities of water, ice, and steam are used for cooling and heating, in industry and homes. Water is an excellent solvent for a variety of chemical substances, as such it is widely used in industrial processes. Water is also central to many sports and other forms of entertainment, such as swimming, pleasure boating, boat racing, surfing, sport fishing, Water is a liquid at the temperatures and pressures that are most adequate for life. Specifically, at atmospheric pressure of 1 bar, water is a liquid between the temperatures of 273.15 K and 373.15 K
Water
–
Water in three states: liquid, solid (
ice), and gas (invisible
water vapor in the air).
Clouds are accumulations of water droplets,
condensed from vapor-saturated air.
Water
–
Impact from a water drop causes an upward "rebound" jet surrounded by circular
capillary waves.
Water
–
Snowflakes by
Wilson Bentley, 1902.
Water
–
Dew drops adhering to a
spider web.
13.
Snake venom
–
Snake venom is highly modified saliva containing zootoxins which facilitates the immobilization and digestion of prey, and defends against threats. It is injected by unique fangs after a bite, and some species are able to spit. The glands have large alveoli in which the venom is stored before being conveyed by a duct to the base of channeled or tubular fangs through which it is ejected. Venoms contain more than 20 different compounds, mostly proteins and polypeptides, charles Lucien Bonaparte, the son of Lucien Bonaparte, younger brother of Napoleon Bonaparte, was the first to establish the proteinaceous nature of snake venom in 1843. Proteins constitute 90-95% of venoms dry weight and they are responsible for almost all of its biological effects, among hundreds, even thousands of proteins found in venom, there are toxins, neurotoxins in particular, as well as nontoxic proteins, and many enzymes, especially hydrolytic ones. Polypeptide toxins include cytotoxins, cardiotoxins, and postsynaptic neurotoxins, which bind to receptors at neuromuscular junctions. Compounds with low molecular weight include metals, peptides, lipids, nucleosides, carbohydrates, amines, and oligopeptides, inter- and intra-species variation in venom chemical composition is geographical and ontogenic. Phosphodiesterases interfere with the cardiac system, mainly to lower the blood pressure. Phospholipase A2 causes hemolysis by lysing the phospholipid membranes of red blood cells. Amino acid oxidases and proteases are used for digestion, amino acid oxidase also triggers some other enzymes and is responsible for the yellow colour of the venom of some species. Hyaluronidase increases tissue permeability to accelerate absorption of other enzymes into tissues, some snake venoms carry fasciculins, like the mambas, which inhibit cholinesterase to make the prey lose muscle control. Snake toxins vary greatly in their functions, two broad classes of toxins found in snake venoms are neurotoxins and hemotoxins. However, there are exceptions — the venom of the spitting cobra, an elapid, consists mainly of cytotoxins, while that of the Mojave rattlesnake. There are numerous types of toxin which both elapids and viperids may carry. The beginning of a new impulse, A) An exchange of ions across the cell membrane sends a depolarizing current towards the end of the nerve cell. B) When the depolarizing current arrives at the nerve cell terminus, the neurotransmitter acetylcholine and it moves across the synapse to the postsynaptic receptors. C) ACh binds to the receptors and transfers the signal to the target cell, fasciculins, These toxins attack cholinergic neurons by destroying acetylcholinesterase. ACh therefore cannot be broken down and stays in the receptor and this causes tetany, which can lead to death
Snake venom
–
Snake toxin
Snake venom
–
Postsynaptic
density
Snake venom
Snake venom
–
European adder (Vipera berus), one fang with a small venom stain in glove, the other still in place
14.
Paradigm
–
Paradigm comes from Greek παράδειγμα, pattern, example, sample from the verb παραδείκνυμι, exhibit, represent, expose and that from παρά, beside, beyond and δείκνυμι, to show, to point out. In rhetoric, paradeigma is known as a type of proof, the purpose of paradeigma is to provide an audience with an illustration of similar occurrences. This illustration is not meant to take the audience to a conclusion, a personal accountant is a good comparison of paradeigma to explain how it is meant to guide the audience. Anaximenes defined paradeigma as, actions that have occurred previously and are similar to, or the opposite of, the original Greek term παράδειγμα was used in Greek texts such as Platos Timaeus as the model or the pattern that the Demiurge used to create the cosmos. In linguistics, Ferdinand de Saussure used paradigm to refer to a class of elements with similarities, normal science proceeds within such a framework or paradigm. A paradigm does not impose a rigid or mechanical approach, the Oxford English Dictionary defines the basic meaning of the term paradigm as a typical example or pattern of something, a pattern or model. e. Firstly, within normal science, the term refers to the set of experiments that are likely to be copied or emulated. Secondly, underpinning this set of exemplars are shared preconceptions, made prior to – and these preconceptions embody both hidden assumptions and elements that he describes as quasi-metaphysical, the interpretations of the paradigm may vary among individual scientists. Kuhn was at pains to point out that the rationale for the choice of exemplars is a way of viewing reality, that view. For well-integrated members of a discipline, its paradigm is so convincing that it normally renders even the possibility of alternatives unconvincing. Such a paradigm is opaque, appearing to be a view of the bedrock of reality itself. The conviction that the current paradigm is reality tends to disqualify evidence that might undermine the paradigm itself and it is the latter that is responsible for the eventual revolutionary overthrow of the incumbent paradigm, and its replacement by a new one. Kuhn used the expression paradigm shift for this process, and likened it to the change that occurs when our interpretation of an ambiguous image flips over from one state to another. This is significant in relation to the issue of incommensurability, an example of a currently accepted paradigm would be the standard model of physics. Mechanisms similar to the original Kuhnian paradigm have been invoked in various disciplines other than the philosophy of science and these include, the idea of major cultural themes, worldviews, ideologies, and mindsets. They have somewhat similar meanings that apply to smaller and larger examples of disciplined thought. In addition, Michel Foucault used the terms episteme and discourse, mathesis and taxinomia, in The Structure of Scientific Revolutions, Kuhn wrote that the successive transition from one paradigm to another via revolution is the usual developmental pattern of mature science. New paradigms tend to be most dramatic in sciences that appear to be stable and mature, at that time, a statement generally attributed to physicist Lord Kelvin famously claimed, There is nothing new to be discovered in physics now
Paradigm
–
The
Flammarion engraving, wood engraving, Paris 1888
15.
Animal testing
–
This approach can be contrasted with field studies in which animals are observed in their natural environments. Examples of applied research include testing, breeding, defense research and toxicology, in education, animal testing is sometimes a component of biology or psychology courses. The practice is regulated to varying degrees in different countries, worldwide it is estimated that the number of vertebrate animals—from zebrafish to non-human primates—ranges from the tens of millions to more than 100 million used annually. In the United States in 2014, official statistics indicate that 834,453 vertebrates were used in research, in the European Union, these species represent 93% of animals used in research. If the same was true in the United States, then the number of animals used in research is estimated to be between 12 and 25 million. One estimate of mice and rats used in the United States alone in 2001 was 80 million, in the European Union in 2011,11.5 million animals were used in research. Mice, rats, fish, amphibians and reptiles together account for over 85% of research animals, most animals are euthanized after being used in an experiment. Supporters of the use of animals in experiments, such as the British Royal Society, the terms animal testing, animal experimentation, animal research, in vivo testing, and vivisection have similar denotations but different connotations. Literally, vivisection means the cutting up of a living animal, the word has a negative connotation, implying torture, suffering, and death. The word vivisection is preferred by those opposed to this research, the earliest references to animal testing are found in the writings of the Greeks in the 2nd and 4th centuries BCE. Aristotle and Erasistratus were among the first to perform experiments on living animals, galen, a physician in 2nd-century Rome, dissected pigs and goats, and is known as the father of vivisection. Animals have repeatedly been used through the history of biomedical research, the founders, in 1831, of the Dublin Zoo were members of the medical profession, interested in studying the animals both while they were alive and when they were dead. In the 1880s, Louis Pasteur convincingly demonstrated the theory of medicine by inducing anthrax in sheep. In the 1880s, Robert Koch infected mice and guinea pigs with anthrax, in the 1890s, Ivan Pavlov famously used dogs to describe classical conditioning. In World War I, German agents infected sheep bound for Russia with anthrax, between 1917 and 1918, the Germans infected mules in Argentina bound for American forces, resulting in the death of 200 mules. Insulin was first isolated from dogs in 1922, and revolutionized the treatment of diabetes, on November 3,1957, a Soviet dog, Laika, became the first of many animals to orbit the earth. In the 1970s, antibiotic treatments and vaccines for leprosy were developed using armadillos and this genetic research progressed rapidly and, in 1996, Dolly the sheep was born, the first mammal to be cloned from an adult cell. Toxicology testing became important in the 20th century, in the 19th century, laws regulating drugs were more relaxed
Animal testing
–
A
Wistar laboratory rat
Animal testing
–
An Experiment on a Bird in an Air Pump, from 1768, by
Joseph Wright
Animal testing
–
Claude Bernard, regarded as the "prince of vivisectors", argued that experiments on animals are "entirely conclusive for the toxicology and hygiene of man".
Animal testing
–
One of
Pavlov 's dogs with a
saliva-catch container and tube surgically implanted in his muzzle, Pavlov Museum, 2005
16.
Lead
–
Lead is a chemical element with atomic number 82 and symbol Pb. When freshly cut, it is bluish-white, it tarnishes to a dull gray upon exposure to air and it is a soft, malleable, and heavy metal with a density exceeding that of most common materials. Lead has the second-highest atomic number of the stable elements. Lead is a relatively unreactive post-transition metal and its weak metallic character is illustrated by its amphoteric nature and tendency to form covalent bonds. Compounds of lead are found in the +2 oxidation state. Exceptions are mostly limited to organolead compounds, like the lighter members of the group, lead exhibits a tendency to bond to itself, it can form chains, rings, and polyhedral structures. Lead is easily extracted from its ores and was known to people in Western Asia. A principal ore of lead, galena, often bears silver, Lead production declined after the fall of Rome and did not reach comparable levels again until the Industrial Revolution. Nowadays, global production of lead is about ten million tonnes annually, Lead has several properties that make it useful, high density, low melting point, ductility, and relative inertness to oxidation. In the late 19th century, lead was recognized as poisonous, Lead is a neurotoxin that accumulates in soft tissues and bones, damaging the nervous system and causing brain disorders and, in mammals, blood disorders. A lead atom has 82 electrons, arranged in a configuration of 4f145d106s26p2. The combined first and second ionization energies—the total energy required to remove the two 6p electrons—is close to that of tin, leads upper neighbor in group 14. This is unusual since ionization energies generally fall going down a group as an elements outer electrons become more distant from the nucleus, the similarity is caused by the lanthanide contraction—the decrease in element radii from lanthanum to lutetium, and the relatively small radii of the elements after hafnium. The contraction is due to shielding of the nucleus by the lanthanide 4f electrons. The combined first four ionization energies of lead exceed those of tin, for this reason lead, unlike tin, mostly forms compounds in which it has an oxidation state of +2, rather than +4. Relativistic effects, which become particularly prominent at the bottom of the periodic table, as a result, the 6s electrons of lead become reluctant to participate in bonding, a phenomenon called the inert pair effect. A related outcome is that the distance between nearest atoms in crystalline lead is unusually long, the lighter group 14 elements form stable or metastable allotropes having the tetrahedrally coordinated and covalently bonded diamond cubic structure. The energy levels of their outer s- and p-orbitals are close enough to allow mixing into four hybrid sp3 orbitals
Lead
–
Lead, 82 Pb
Lead
–
A sample of freshly solidified lead (from molten state)
Lead
–
World lead production peaking in the
Roman period and the rising
Industrial Revolution
Lead
–
Lead
ingots from
Roman Britain on display at the
Wells and Mendip Museum
17.
Mercury (element)
–
Mercury is a chemical element with symbol Hg and atomic number 80. It is commonly known as quicksilver and was formerly named hydrargyrum, Mercury occurs in deposits throughout the world mostly as cinnabar. The red pigment vermilion is obtained by grinding natural cinnabar or synthetic mercuric sulfide, likewise, mechanical pressure gauges and electronic strain gauge sensors have replaced mercury sphygmomanometers. Mercury remains in use in research applications and in amalgam for dental restoration in some locales. It is used in fluorescent lighting, electricity passed through mercury vapor in a fluorescent lamp produces short-wave ultraviolet light which then causes the phosphor in the tube to fluoresce, making visible light. Mercury poisoning can result from exposure to water-soluble forms of mercury, Mercury is a heavy, silvery-white liquid metal. Compared to other metals, it is a conductor of heat. It has a point of −38.83 °C and a boiling point of 356.73 °C. Upon freezing, the volume of mercury decreases by 3. 59%, the coefficient of volume expansion is 181.59 × 10−6 at 0 °C,181.71 × 10−6 at 20 °C and 182.50 × 10−6 at 100 °C. Solid mercury is malleable and ductile and can be cut with a knife, because this configuration strongly resists removal of an electron, mercury behaves similarly to noble gases, which form weak bonds and hence melt at low temperatures. The stability of the 6s shell is due to the presence of a filled 4f shell, an f shell poorly screens the nuclear charge that increases the attractive Coulomb interaction of the 6s shell and the nucleus. Like silver, mercury reacts with hydrogen sulfide. Mercury reacts with solid sulfur flakes, which are used in mercury spill kits to absorb mercury, Mercury dissolves many other metals such as gold and silver to form amalgams. Iron is an exception, and iron flasks have traditionally used to trade mercury. Several other first row transition metals with the exception of manganese, copper, other elements that do not readily form amalgams with mercury include platinum. Sodium amalgam is a reducing agent in organic synthesis, and is also used in high-pressure sodium lamps. Mercury readily combines with aluminium to form a mercury-aluminium amalgam when the two pure metals come into contact, since the amalgam destroys the aluminium oxide layer which protects metallic aluminium from oxidizing in-depth, even small amounts of mercury can seriously corrode aluminium. For this reason, mercury is not allowed aboard an aircraft under most circumstances because of the risk of it forming an amalgam with exposed aluminium parts in the aircraft, Mercury embrittlement is the most common type of liquid metal embrittlement
Mercury (element)
–
Mercury, 80 Hg
Mercury (element)
–
Spectral lines of mercury (UV not seen)
Mercury (element)
–
A
pound coin (density ~7.6 g/cm 3) floats in mercury due to the combination of the
buoyant force and
surface tension.
Mercury (element)
–
Mercury-discharge spectral calibration lamp
18.
Hydrofluoric acid
–
Hydrofluoric acid is a solution of hydrogen fluoride in water. It is a precursor to almost all compounds, including pharmaceuticals such as fluoxetine, diverse materials such as PTFE. It is a solution that is highly corrosive, capable of dissolving many materials. Its ability to dissolve glass has been known since the 17th century, because of its high reactivity toward glass and moderate reactivity toward many metals, hydrofluoric acid is usually stored in plastic containers. Hydrogen fluoride gas is a poison that may immediately and permanently damage lungs. Aqueous hydrofluoric acid is a contact-poison with the potential for deep, initially painless burns, by interfering with body calcium metabolism, the concentrated acid may also cause systemic toxicity and eventual cardiac arrest and fatality, after contact with as little as 160 cm2 of skin. Hydrofluoric acid is classified as an acid because of its lower dissociation constant compared to the strong acids. Hydrofluoric acid is produced by treatment of the mineral fluorite with concentrated sulfuric acid, apatite sources typically contain a few percent of fluoroapatite, acid digestion of which releases a gaseous stream consisting of sulfur dioxide, water, and HF, as well as particulates. After separation from the solids, the gases are treated with sulfuric acid, owing to the corrosive nature of HF, its production is accompanied by the dissolution of silicate minerals, and, in this way, significant amounts of fluorosilicic acid are generated. Hydrofluoric acid has a variety of uses in industry and research and it is used as a starting material or intermediate in industrial chemistry, mining, refining, glass finishing, silicon chip manufacturing, and in cleaning. In a standard oil refinery known as alkylation, isobutane is alkylated with low-molecular-weight alkenes in the presence of the strong acid catalyst derived from hydrofluoric acid. The catalyst protonates the alkenes to produce reactive carbocations, which alkylate isobutane, the reaction is carried out at mild temperatures in a two-phase reaction. The principal use of acid is in organofluorine chemistry. Many organofluorine compounds are prepared using HF as the source, including Teflon, fluoropolymers, fluorocarbons. Most high-volume inorganic fluoride compounds are prepared from hydrofluoric acid, foremost are Na3AlF6, cryolite, and AlF3, aluminium trifluoride. A molten mixture of these serves as a high-temperature solvent for the production of metallic aluminium. Given concerns about fluorides in the environment, alternative technologies are being sought, other inorganic fluorides prepared from hydrofluoric acid include sodium fluoride and uranium hexafluoride. In metalworking, hydrofluoric acid is used as an agent to remove oxides and other impurities from stainless
Hydrofluoric acid
Hydrofluoric acid
–
Hydrofluoric acid
Hydrofluoric acid
–
Wet etching tanks
Hydrofluoric acid
–
A hydrofluoric acid burn of the hand
19.
Chlorine
–
Chlorine is a chemical element with symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the table and its properties are mostly intermediate between them. Chlorine is a gas at room temperature. It is an extremely reactive element and a strong oxidising agent, among the elements, it has the highest electron affinity, the most common compound of chlorine, sodium chloride, has been known since ancient times. Around 1630, chlorine gas was first synthesised in a chemical reaction, Carl Wilhelm Scheele wrote a description of chlorine gas in 1774, supposing it to be an oxide of a new element. In 1809, chemists suggested that the gas might be an element, and this was confirmed by Sir Humphry Davy in 1810. Because of its reactivity, all chlorine in the Earths crust is in the form of ionic chloride compounds. It is the second-most abundant halogen and twenty-first most abundant chemical element in Earths crust and these crustal deposits are nevertheless dwarfed by the huge reserves of chloride in seawater. Elemental chlorine is produced from brine by electrolysis. The high oxidising potential of chlorine led to the development of commercial bleaches and disinfectants. As a common disinfectant, elemental chlorine and chlorine-generating compounds are used directly in swimming pools to keep them clean. Elemental chlorine at high concentrations is extremely dangerous and poisonous for all living organisms, in the form of chloride ions, chlorine is necessary to all known species of life. Other types of compounds are rare in living organisms. In the upper atmosphere, chlorine-containing organic molecules such as chlorofluorocarbons have been implicated in ozone depletion, small quantities of elemental chlorine are generated by oxidation of chloride to hypochlorite in neutrophils as part of the immune response against bacteria. Its importance in food was very well known in antiquity and was sometimes used as payment for services for Roman generals. Around 1630, chlorine was recognized as a gas by the Flemish chemist, the element was first studied in detail in 1774 by Swedish chemist Carl Wilhelm Scheele, and he is credited with the discovery. He called it dephlogisticated muriatic acid air since it is a gas and he failed to establish chlorine as an element, mistakenly thinking that it was the oxide obtained from the hydrochloric acid. He named the new element within this oxide as muriaticum, in 1809, Joseph Louis Gay-Lussac and Louis-Jacques Thénard tried to decompose dephlogisticated muriatic acid air by reacting it with charcoal to release the free element muriaticum
Chlorine
–
A glass container filled with chlorine gas
Chlorine
–
Chlorine, liquefied under a pressure of 7.4 bar at room temperature, displayed in a quartz ampule embedded in
acrylic glass.
Chlorine
–
Carl Wilhelm Scheele
Chlorine
–
Liquid chlorine analysis
20.
Organic compound
–
An organic compound is virtually any chemical compound that contains carbon, although a consensus definition remains elusive and likely arbitrary. Organic compounds are rare terrestrially, but of importance because all known life is based on organic compounds. The most basic petrochemicals are considered the building blocks of organic chemistry, for historical reasons discussed below, a few types of carbon-containing compounds, such as carbides, carbonates, simple oxides of carbon, and cyanides are considered inorganic. The distinction between organic and inorganic compounds, while useful in organizing the vast subject of chemistry. Organic chemistry is the science concerned with all aspects of organic compounds, Organic synthesis is the methodology of their preparation. The word organic is historical, dating to the 1st century, for many centuries, Western alchemists believed in vitalism. This is the theory that certain compounds could be synthesized only from their classical elements—earth, water, air, vitalism taught that these organic compounds were fundamentally different from the inorganic compounds that could be obtained from the elements by chemical manipulation. Vitalism survived for a while even after the rise of modern atomic theory and it first came under question in 1824, when Friedrich Wöhler synthesized oxalic acid, a compound known to occur only in living organisms, from cyanogen. A more decisive experiment was Wöhlers 1828 synthesis of urea from the inorganic salts potassium cyanate, urea had long been considered an organic compound, as it was known to occur only in the urine of living organisms. Wöhlers experiments were followed by others, in which increasingly complex organic substances were produced from inorganic ones without the involvement of any living organism. Even though vitalism has been discredited, scientific nomenclature retains the distinction between organic and inorganic compounds, still, even the broadest definition requires excluding alloys that contain carbon, including steel. The C-H definition excludes compounds that are considered organic, neither urea nor oxalic acid is organic by this definition, yet they were two key compounds in the vitalism debate. The IUPAC Blue Book on organic nomenclature specifically mentions urea and oxalic acid, other compounds lacking C-H bonds but traditionally considered organic include benzenehexol, mesoxalic acid, and carbon tetrachloride. Mellitic acid, which contains no C-H bonds, is considered an organic substance in Martian soil. The C-H bond-only rule also leads to somewhat arbitrary divisions in sets of carbon-fluorine compounds, for example, CF4 would be considered by this rule to be inorganic, whereas CF3H would be organic. Organic compounds may be classified in a variety of ways, one major distinction is between natural and synthetic compounds. Another distinction, based on the size of organic compounds, distinguishes between small molecules and polymers, natural compounds refer to those that are produced by plants or animals. Many of these are extracted from natural sources because they would be more expensive to produce artificially
Organic compound
–
Methane is one of the simplest organic compounds
21.
Radioactive
–
A material containing such unstable nuclei is considered radioactive. Certain highly excited short-lived nuclear states can decay through neutron emission, or more rarely, however, for a collection of atoms, the collections expected decay rate is characterized in terms of their measured decay constants or half-lives. This is the basis of radiometric dating, the half-lives of radioactive atoms have no known upper limit, spanning a time range of over 55 orders of magnitude, from nearly instantaneous to far longer than the age of the universe. A radioactive nucleus with spin can have no defined orientation. If there are multiple particles produced during a single decay, as in decay, their relative angular distribution. Such a parent process could be a previous decay, or a nuclear reaction, the decaying nucleus is called the parent radionuclide, and the process produces at least one daughter nuclide. Except for gamma decay or internal conversion from an excited state. When the number of changes, an atom of a different chemical element is created. The first decay processes to be discovered were alpha decay, beta decay, alpha decay occurs when the nucleus ejects an alpha particle. This is the most common process of emitting nucleons, but highly excited nuclei can eject single nucleons, or in the case of cluster decay, specific light nuclei of other elements. Beta decay occurs when the nucleus emits an electron or positron, the nucleus may capture an orbiting electron, causing a proton to convert into a neutron in a process called electron capture. All of these result in a well-defined nuclear transmutation. By contrast, there are radioactive decay processes that do not result in a nuclear transmutation, another type of radioactive decay results in products that vary, appearing as two or more fragments of the original nucleus with a range of possible masses. For a summary table showing the number of stable and radioactive nuclides in each category, there are 29 naturally occurring chemical elements on Earth that are radioactive. They are those that contain 34 radionuclides that date before the time of formation of the solar system, well-known examples are uranium and thorium, but also included are naturally occurring long-lived radioisotopes, such as potassium-40. Radioactivity was discovered in 1896 by the French scientist Henri Becquerel and these materials glow in the dark after exposure to light, and he suspected that the glow produced in cathode ray tubes by X-rays might be associated with phosphorescence. He wrapped a photographic plate in black paper and placed various phosphorescent salts on it, all results were negative until he used uranium salts. The uranium salts caused a blackening of the plate in spite of the plate being wrapped in black paper and these radiations were given the name Becquerel Rays
Radioactive
–
Pierre and Marie Curie in their Paris laboratory, before 1907
Radioactive
–
Alpha decay is one type of radioactive decay, in which an atomic nucleus emits an
alpha particle, and thereby transforms (or "decays") into an atom with a
mass number decreased by 4 and
atomic number decreased by 2.
Radioactive
–
Taking an X-ray image with early
Crookes tube apparatus in 1896. The Crookes tube is visible in the centre. The standing man is viewing his hand with a
fluoroscope screen; this was a common way of setting up the tube. No precautions against radiation exposure are being taken; its hazards were not known at the time.
Radioactive
–
Gamma-ray energy spectrum of uranium ore (inset). Gamma-rays are emitted by decaying
nuclides, and the gamma-ray energy can be used to characterize the decay (which nuclide is decaying to which). Here, using the gamma-ray spectrum, several nuclides that are typical of the decay chain of 238 U have been identified: 226 Ra, 214 Pb, 214 Bi.
22.
Uranium
–
Uranium is a chemical element with symbol U and atomic number 92. It is a metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons, Uranium is weakly radioactive because all its isotopes are unstable. The most common isotopes in natural uranium are uranium-238 and uranium-235, Uranium has the highest atomic weight of the primordially occurring elements. Its density is about 70% higher than that of lead, and it occurs naturally in low concentrations of a few parts per million in soil, rock and water, and is commercially extracted from uranium-bearing minerals such as uraninite. In nature, uranium is found as uranium-238, uranium-235, Uranium decays slowly by emitting an alpha particle. The half-life of uranium-238 is about 4.47 billion years, many contemporary uses of uranium exploit its unique nuclear properties. Uranium-235 is the naturally occurring fissile isotope, which makes it widely used in nuclear power plants. However, because of the amounts found in nature, uranium needs to undergo enrichment so that enough uranium-235 is present. Uranium-238 is fissionable by fast neutrons, and is fertile, meaning it can be transmuted to fissile plutonium-239 in a nuclear reactor, another fissile isotope, uranium-233, can be produced from natural thorium and is also important in nuclear technology. In sufficient concentration, these maintain a sustained nuclear chain reaction. This generates the heat in nuclear reactors, and produces the fissile material for nuclear weapons. Depleted uranium is used in kinetic energy penetrators and armor plating, Uranium is used as a colorant in uranium glass, producing lemon yellow to green colors. Uranium glass fluoresces green in ultraviolet light and it was also used for tinting and shading in early photography. The 1789 discovery of uranium in the mineral pitchblende is credited to Martin Heinrich Klaproth, eugène-Melchior Péligot was the first person to isolate the metal and its radioactive properties were discovered in 1896 by Henri Becquerel. An ensuing arms race during the Cold War between the United States and the Soviet Union produced tens of thousands of weapons that used uranium metal. The security of those weapons and their fissile material following the breakup of the Soviet Union in 1991 is a concern for public health. When refined, uranium is a white, weakly radioactive metal
Uranium
–
Uranium, 92 U
Uranium
–
Depleted uranium is used by various militaries as high-density penetrators
Uranium
–
The most visible civilian use of uranium is as the thermal power source used in
nuclear power plants
Uranium
–
Uranium glass glowing under
UV light
23.
Radium
–
Radium is a chemical element with symbol Ra and atomic number 88. It is the element in group 2 of the periodic table. Pure radium is silvery-white, but it combines with nitrogen on exposure to air. All isotopes of radium are highly radioactive, with the most stable isotope being radium-226, when radium decays, ionizing radiation is a product, which can excite fluorescent chemicals and cause radioluminescence. Radium, in the form of chloride, was discovered by Marie. They extracted the radium compound from uraninite and published the discovery at the French Academy of Sciences five days later, Radium was isolated in its metallic state by Marie Curie and André-Louis Debierne through the electrolysis of radium chloride in 1911. In nature, radium is found in uranium and thorium ores in trace amounts as small as a seventh of a gram per ton of uraninite. Radium is not necessary for living organisms, and adverse effects are likely when it is incorporated into biochemical processes because of its radioactivity. Today, these applications are no longer in vogue because radiums toxicity has since become known. Radium is the heaviest known alkaline earth metal and is the only member of its group. Its physical and chemical properties most closely resemble its lighter congener barium, pure radium is a volatile silvery-white metal, although its lighter congeners calcium, strontium, and barium have a slight yellow tint. Its color rapidly vanishes in air, yielding a layer of radium nitride. Its melting point is either 700 °C or 960 °C and its point is 1,737 °C. Both of these values are lower than those of barium. Like barium and the metals, radium crystallizes in the body-centered cubic structure at standard temperature and pressure. Radium has a density of 5, Radium, like barium, is a highly reactive metal and always exhibits its group oxidation state of +2. It forms the colorless Ra2+ cation in aqueous solution, which is highly basic, the values for barium and radium are almost exactly the same as those of the heavier alkali metals potassium, rubidium, and caesium. Solid radium compounds are white as radium ions provide no specific coloring, insoluble radium compounds coprecipitate with all barium, most strontium, and most lead compounds
Radium
–
Radium, 88 Ra
Radium
–
Marie and Pierre Curie experimenting with radium, a drawing by
André Castaigne
Radium
–
Glass tube of radium chloride kept by the US Bureau of Standards that served as the primary standard of radioactivity for the United States in 1927.
Radium
–
Self-luminous white paint which contains radium on the face and hand of an old clock.
24.
Ionizing radiation
–
Ionizing radiation is radiation that carries enough energy to free electrons from atoms or molecules, thereby ionizing them. Ionizing radiation is made up of energetic particles, ions or atoms moving at high speeds. The boundary between ionizing and non-ionizing electromagnetic radiation that occurs in the ultraviolet is not sharply defined, since different molecules, conventional definition places the boundary at a photon energy between 10 eV and 33 eV in the ultraviolet. Typical ionizing subatomic particles from radioactivity include alpha particles, beta particles, almost all products of radioactive decay are ionizing because the energy of radioactive decay is typically far higher than that required to ionize. Cosmic rays are generated by stars and certain events such as supernova explosions. Cosmic rays may also produce radioisotopes on Earth, which in turn decay, cosmic rays and the decay of radioactive isotopes are the primary sources of natural ionizing radiation on Earth referred to as background radiation. Ionizing radiation can also be generated artificially using X-ray tubes, particle accelerators, ionizing radiation is invisible and not directly detectable by human senses, so radiation detection instruments such as Geiger counters are required to detect it. However, it can cause emission of light upon interaction with matter, such as in Cherenkov radiation. Exposure to ionizing radiation damage to living tissue, and can result in mutation, radiation sickness, cancer. Ionizing radiation is categorized by the nature of the particles or electromagnetic waves that create the ionizing effect and these have different ionization mechanisms, and may be grouped as directly or indirectly ionizing. Any charged massive particle can ionize atoms directly by fundamental interaction through the Coulomb force if it carries sufficient kinetic energy and this includes atomic nuclei, electrons, muons, charged pions, protons, and energetic charged nuclei stripped of their electrons. When moving at relativistic speeds these particles have enough energy to be ionizing. For example, an alpha particle is ionizing, but moves at about 5% c. Natural cosmic rays are made up primarily of protons but also include heavier atomic nuclei like helium ions. Pions can also be produced in large amounts in particle accelerators, alpha particles consist of two protons and two neutrons bound together into a particle identical to a helium nucleus. Alpha particle emissions are produced in the process of alpha decay. Alpha particles are named after the first letter in the Greek alphabet, the symbol for the alpha particle is α or α2+. Because they are identical to helium nuclei, they are sometimes written as He2+ or 4 2He2+ indicating a Helium ion with a +2 charge
Ionizing radiation
–
Ionized air glows blue around a beam of particulate ionizing radiation from a
cyclotron
Ionizing radiation
–
Ionizing radiation hazard symbol
25.
Immune system
–
The immune system is a host defense system comprising many biological structures and processes within an organism that protects against disease. To function properly, a system must detect a wide variety of agents, known as pathogens, from viruses to parasitic worms. In many species, the system can be classified into subsystems, such as the innate immune system versus the adaptive immune system. In humans, the barrier, blood–cerebrospinal fluid barrier, and similar fluid–brain barriers separate the peripheral immune system from the neuroimmune system. Even simple unicellular organisms such as bacteria possess a rudimentary immune system in the form of enzymes that protect against bacteriophage infections, other basic immune mechanisms evolved in ancient eukaryotes and remain in their modern descendants, such as plants and invertebrates. These mechanisms include phagocytosis, antimicrobial peptides called defensins, and the complement system, jawed vertebrates, including humans, have even more sophisticated defense mechanisms, including the ability to adapt over time to recognize specific pathogens more efficiently. Adaptive immunity creates immunological memory after a response to a specific pathogen. This process of acquired immunity is the basis of vaccination, disorders of the immune system can result in autoimmune diseases, inflammatory diseases and cancer. Immunodeficiency occurs when the system is less active than normal. In humans, immunodeficiency can either be the result of a disease such as severe combined immunodeficiency, acquired conditions such as HIV/AIDS. In contrast, autoimmunity results from an immune system attacking normal tissues as if they were foreign organisms. Common autoimmune diseases include Hashimotos thyroiditis, rheumatoid arthritis, diabetes mellitus type 1, immunology covers the study of all aspects of the immune system. Immunology is a science that examines the structure and function of the immune system and it originates from medicine and early studies on the causes of immunity to disease. The earliest known reference to immunity was during the plague of Athens in 430 BC, thucydides noted that people who had recovered from a previous bout of the disease could nurse the sick without contracting the illness a second time. In the 18th century, Pierre-Louis Moreau de Maupertuis made experiments with scorpion venom and observed that certain dogs and this and other observations of acquired immunity were later exploited by Louis Pasteur in his development of vaccination and his proposed germ theory of disease. Pasteurs theory was in opposition to contemporary theories of disease. It was not until Robert Kochs 1891 proofs, for which he was awarded a Nobel Prize in 1905, viruses were confirmed as human pathogens in 1901, with the discovery of the yellow fever virus by Walter Reed. Immunology made an advance towards the end of the 19th century, through rapid developments, in the study of humoral immunity
Immune system
–
A
scanning electron microscope image of a single
neutrophil (yellow), engulfing
anthrax bacteria (orange)
Immune system
–
A
scanning electron microscope image of normal circulating human
blood. One can see
red blood cells, several knobby white blood cells including
lymphocytes, a
monocyte, a
neutrophil, and many small disc-shaped
platelets.
Immune system
–
An antibody is made up of two heavy chains and two light chains. The unique variable region allows an antibody to recognize its matching antigen.
Immune system
–
The time-course of an immune response begins with the initial pathogen encounter, (or initial vaccination) and leads to the formation and maintenance of active immunological memory.
26.
Venom
–
Venom is a form of toxin secreted by an animal for the purpose of causing harm to another. The potency of different venoms varies, lethal venoms are often characterised by the lethal dose, expressed in terms of mass fraction. Utilization of venom across a number of species demonstrates an example of convergent evolution. It is difficult to exactly how this trait came to be so intensely widespread. The multigene families that encode the toxins of venomous animals are actively selected on, venoms adapt to their environment and victims and accordingly evolve to become maximally efficient on a predator’s particular prey. Consequently, venoms become specialized to a standard diet. Venomous animals resulted in 57,000 human deaths in 2013, in insects such as bees and wasps, the stinger is a modified egg-laying device — the ovipositor. In Polistes fuscatus, the female releases a venom that contains a sex pheromone that induces copulatory behavior in males. In Polistes exclamans, venom is used as a pheromone, coordinating a response with from the nest. In Dolichovespula arenaria, the spraying of venom out of their sting that has been seen from workers in large colonies. In other cases like Parischnogaster striatula, the venom is applied all over their body in order to make themselves immune to certain harmful diseases. Some cases like the venom from Agelaia pallipes have significant inhibitory effects on biological processes like chemotaxis and hemolysis which can lead to organ failure. This prevents the spread of disease throughout the colony, the use of venom is much more widespread than just these examples. Other insects, such as bugs and many ants, also produce venom. At least one ant species has shown to use venom topically for the sterilisation of pathogens. There are many other invertebrates, including jellyfish, cone snails. The box jellyfish is the most venomous jellyfish in the world, there are only a few known species of venomous amphibians, certain salamandrid salamanders can extrude sharp venom-tipped ribs. The reptiles most known to use venom are snakes, some species of which inject venom into their prey via fangs, snake venom is produced by glands below the eye and delivered to the victim through tubular or channeled fangs
Venom
–
Venomous Animals
Venom
–
Wasp sting, with a droplet of venom
27.
Coal
–
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure. Coal is composed primarily of carbon, along with quantities of other elements, chiefly hydrogen, sulfur, oxygen. A fossil fuel, coal forms when plant matter is converted into peat, which in turn is converted into lignite, then sub-bituminous coal, after that bituminous coal. This involves biological and geological processes that take place over time, throughout history, coal has been used as an energy resource, primarily burned for the production of electricity and heat, and is also used for industrial purposes, such as refining metals. Coal is the largest source of energy for the generation of electricity worldwide, the extraction of coal, its use in energy production and its byproducts are all associated with environmental and health effects including climate change. Coal is extracted from the ground by coal mining, since 1983, the worlds top coal producer has been China. In 2015 China produced 3,747 million tonnes of coal –47. 7% of 7,861 million tonnes world coal production, in 2015 other large producers were United States, India, European Union and Australia. The word originally took the col in Old English, from Proto-Germanic *kula. In Old Turkic languages, kül is ash, cinders, öčür is quench, the compound charcoal in Turkic is öčür kül, literally quenched ashes, cinders, coals with elided anlaut ö- and inflection affixes -ülmüş. At various times in the geologic past, the Earth had dense forests in low-lying wetland areas, due to natural processes such as flooding, these forests were buried underneath soil. As more and more soil deposited over them, they were compressed, the temperature also rose as they sank deeper and deeper. As the process continued the plant matter was protected from biodegradation and oxidation and this trapped the carbon in immense peat bogs that were eventually covered and deeply buried by sediments. Under high pressure and high temperature, dead vegetation was slowly converted to coal, as coal contains mainly carbon, the conversion of dead vegetation into coal is called carbonization. The wide, shallow seas of the Carboniferous Period provided ideal conditions for coal formation, the exception is the coal gap in the Permian–Triassic extinction event, where coal is rare. Coal is known from Precambrian strata, which predate land plants — this coal is presumed to have originated from residues of algae, in its dehydrated form, peat is a highly effective absorbent for fuel and oil spills on land and water. It is also used as a conditioner for soil to make it able to retain. Lignite, or brown coal, is the lowest rank of coal, jet, a compact form of lignite, is sometimes polished and has been used as an ornamental stone since the Upper Palaeolithic
Coal
–
Anthracite coal
Coal
–
Bituminous coal
Coal
–
Coastal exposure of the Point Aconi Seam (Nova Scotia)
Coal
–
Coal miner in Britain, 1942
28.
Asbestos
–
They are commonly known by their colors, as blue asbestos, brown asbestos, white asbestos, and green asbestos. It was used in applications as electrical insulation for hotplate wiring. When asbestos is used for its resistance to fire or heat and these desirable properties made asbestos very widely used. Prolonged inhalation of asbestos fibers can cause serious and fatal illnesses including cancer, mesothelioma. Concern of asbestos-related illness in modern times began in the 20th century, by the 1980s and 1990s, asbestos trade and use were heavily restricted, phased out, or banned outright in an increasing number of countries. S. History and a much lesser legal issue in most other countries involved, asbestos-related liability also remains an ongoing concern for many manufacturers, insurers and reinsurers. Asbestos derives from the ancient Greek ἄσβεστος, meaning unquenchable or inextinguishable, the word is pronounced /æsˈbɛstəs/, /æzˈbɛstəs/ or /æzˈbɛstɒs/. Six mineral types are defined by the United States Environmental Protection Agency as asbestos including those belonging to the serpentine class, all six asbestos mineral types are known to be human carcinogens. The visible fibers are themselves composed of millions of microscopic fibrils that can be released by abrasion. Chrysotile is the member of the serpentine class. 12001-29-5, is obtained from rocks which are common throughout the world. Its idealized chemical formula is Mg34, chrysotile appears under the microscope as a white fiber. Chrysotile has been used more than any type and accounts for about 95% of the asbestos found in buildings in America. Chrysotile is more flexible than amphibole types of asbestos, and can be spun, the most common use was corrugated asbestos cement roofing primarily for outbuildings, warehouses and garages. It may also be found in sheets or panels used for ceilings and sometimes for walls, chrysotile has been a component in joint compound and some plasters. Amosite, crocidolite, tremolite, anthophyllite and actinolite are members of the amphibole class, one formula given for amosite is Fe7Si8O222. Amosite is seen under a microscope as a grey-white vitreous fiber and it is found most frequently as a fire retardant in thermal insulation products, asbestos insulating board and ceiling tiles. 12001-28-4, is the form of the amphibole riebeckite, found primarily in southern Africa
Asbestos
–
Fibrous
tremolite asbestos on
muscovite
Asbestos
–
Asbestos
Asbestos
–
Blue asbestos (crocidolite) from
Wittenoom, Western Australia. The ruler is 1 cm.
Asbestos
–
Blue asbestos, teased to show the fibrous nature of the mineral (from mine at
Wittenoom, Western Australia)
29.
Carcinogens
–
A carcinogen is any substance, radionuclide, or radiation that is an agent directly involved in causing cancer. This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes, several radioactive substances are considered carcinogens, but their carcinogenic activity is attributed to the radiation, for example gamma rays and alpha particles, which they emit. Common examples of non-radioactive carcinogens are inhaled asbestos, certain dioxins, although the public generally associates carcinogenicity with synthetic chemicals, it is equally likely to arise in both natural and synthetic substances. Carcinogens are not necessarily immediately toxic, thus their effect can be insidious, Cancer is any disease in which normal cells are damaged and do not undergo programmed cell death as fast as they divide via mitosis. Usually, severe DNA damage leads to apoptosis, but if the cell death pathway is damaged. Aflatoxin B1, which is produced by the fungus Aspergillus flavus growing on stored grains, nuts and peanut butter, is an example of a potent, certain viruses such as hepatitis B and human papilloma virus have been found to cause cancer in humans. The first one shown to cause cancer in animals is Rous sarcoma virus, other infectious organisms which cause cancer in humans include some bacteria and helminths. Dioxins and dioxin-like compounds, benzene, kepone, EDB, 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, 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, however, in some cases, these reactions can also convert a less toxic carcinogen into a more toxic carcinogen. 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 and this is the mechanism behind the carcinogenicity of benzopyrene in tobacco smoke, other aromatics, aflatoxin and mustard gas. Carcinogenicity of radiation depends on the type of radiation, type of exposure, for example, alpha radiation has low penetration and is not a hazard outside the body, but emitters are carcinogenic when inhaled or ingested. Low-level ionizing radiation may induce irreparable DNA damage leading to pre-mature aging, not all types of electromagnetic radiation are carcinogenic. Higher-energy radiation, including radiation, x-rays, and gamma radiation, generally is carcinogenic. For most people, ultraviolet radiations from sunlight is the most common cause of skin cancer, in Australia, where people with pale skin are often exposed to strong sunlight, melanoma is the most common cancer diagnosed in people aged 15–44 years. Substances or foods irradiated with electrons or electromagnetic radiation are not carcinogenic, in contrast, non-electromagnetic neutron radiation produced inside nuclear reactors can produce secondary radiation through nuclear transmutation. Chemicals used in processed and cured such as some brands of bacon, sausages
Carcinogens
–
The
international pictogram for chemicals that are sensitising,
mutagenic, carcinogenic or
toxic to reproduction.
