( A Through D )

A



acids

An acid is a substance that dissolves in water, producing a solution rich in hydrogen ions. Weak acids, such as citric acid or vinegar (acetic acid), have a sour taste. The stronger mineral acids, such as sulphuric acid, are corrosive and readily attack many substances, including metals.

Only the weaker acids were available to the ancient alchemists, because the mineral acids are difficult to prepare. From around the 13th century, alchemists in Europe began to have access to stronger acids, allowing them to extend their discoveries.



alkalis

An alkali is a substance that dissolves in water, producing a solution poor in hydrogen ions. Alkalis have a slippery feel – soap is a weak alkali. Strong alkalis are caustic, and are able to react with many substances. They neutralise acids.

Alkalis available to the alchemists included potash (potassium hydroxide), extracted from the ashes of burnt plants, and ammonia, which could be obtained from the distillation of urine.



American Type Culture Collection (also see culture collections)

The American Type Culture Collection (ATCC) is a collection of micro-organisms which is open to all scientists throughout the world whether they work for private industry, governments or academic organisations.

Full information about the services they provide can be found at: www.atcc.org



amine

An amine is a compound that contains the chemical grouping of a nitrogen atom bonded to one carbon atom and two hydrogen atoms. Many neurotransmitters have an amine group as part of their structure and these are called amine neurotransmitters. They are involved in reducing pain or stress, replacing them with pleasure or a feeling of well-being.



anthrax

Anthrax is a disease caused by the bacterium Bacillus anthracis.

Human anthrax has three major clinical forms depending on which part of the body is exposed to the anthrax spore: cutaneous (skin), inhalation and gastrointestinal.

If untreated, anthrax in all forms can lead to septicaemia and death. Early treatment with antibiotics usually results in a cure for cutaneous anthrax but recovery rates for the gastrointestinal and inhalation forms are much lower.

Anthrax is a naturally occurring disease and can be contracted from infected livestock and wild animals or contaminated animal products. Human-to-human transmission is extremely rare and only reported with cutaneous anthrax.



Aristotle

Aristotle was a Greek philosopher (384-322 BC). He was a pupil of Plato and the tutor of Alexander the Great. He studied a vast range of subjects, and his work is the foundation of much of Western thinking. Aristotle believed that to understand the world it is necessary to actively observe parts of it, rather than deduce its nature by logical thought alone. Aristotle thus influenced the modern scientific process, with its emphasis on experiments and observation.



atomism (also see atoms)

Atomism is the idea that all matter is made up of tiny, indivisible fragments, too small to be seen. The many forms of matter are based on various combinations of different types of these atoms.

Democritus developed the first atomic theory in Greece in the 5th century BC. His theory was not simply an attempt to explain the mechanics of the physical world, but a philosophy to explain why existence is full of many, continuously changing forms.

Modern atomic theory was developed by Dalton in the late 18th century AD. It was more concerned with rationalising the behaviour of the many chemical compounds that had been studied by then.



atoms

Atomic theory says that all matter is made of atoms: tiny particles that cannot be created or destroyed by chemical means. Like building blocks, atoms can join up with each other. Some substances are made of only one type of atom; these are elements, such as gold and oxygen. Other substances are made up of combinations of different elements in various orders and proportions for example: carbon dioxide, polythene and water. The number of different types of atoms in the Universe is low, but by combining them in different ways, all the substances around us can be made.

B



Babylonia

Babylonia was a civilisation of ancient southern Mesopotamia (south of modern day Baghdad, Iraq) that flourished between the 18th and 6th centuries BC.

Babylonian culture made great strides forward in many fields, including maths and astronomy. We still use some of their innovations, including our time-keeping system, the division of a circle into 360 degrees, and the signs of the zodiac.



Bacon, Sir Francis

Sir Francis Bacon (1561-1626) was an English politician and philosopher whose views on the scientific method were highly influential.

Bacon was not particularly successful as a politician, taking a long time to gain high office then soon losing it under suspicion of taking bribes. However, this gave him more time to devote to scientific studies.

Bacon emphasised the role of logical induction in the scientific process – by accumulating evidence from many experiments, specific results can then be used to derive general laws that describe Nature. This approach became central to scientists' methods.

Bacon died performing a scientific experiment. He caught a chill while investigating if snow would delay the decay of a chicken.



bacteria

Bacteria is the plural of bacterium. Bacteria are microscopic organisms which can multiply rapidly by splitting in two. Not all bacteria are 'bad' and spread disease, some are necessary for our bodies to work properly.



base metals

Base metals were reactive metals such as lead or iron. These impure materials could be transmuted by alchemy into the perfection of gold. Gold was regarded as the purest, most perfect metal, due to its beauty and unreactivity with other materials.



biological agents

Biological agents are living micro-organisms (bacteria, viruses and fungi) and the toxins produced by these organisms. They can spread diseases that can affect humans, animals or crops.



Biological Weapons Treaty 1972

The Biological Weapons Convention (BWC) was signed in 1972 and came into force in 1975. The 144 signatories to the convention (including UK, US, Russian Federation, Iraq and Afghanistan) agreed to prevent research, development and production of biological weapons as well as to destroy existing stockpiles.

The full text of the BWC can be found at: www.stimson.org/cwc/bwctext.htm



biotechnology

Biotechnology is a branch of biology that manipulates living organisms to generate useful products such as pharmaceuticals. Genetic engineering is one of the tools used by biotechnologists.



bioterrorism

Bioterrorism is the use, or the threat of use, of living micro-organisms (bacteria, viruses and fungi) capable of causing death and illness amongst humans, animals or crops in an attempt to intimidate or coerce a population or government.



biowarfare

The definition of biowarfare, or germ warfare, is the deliberate use of biological agents of disease to cause harm to a targeted people. This can be done directly, by bringing the people into contact with the agents. Or it can be done indirectly, by infecting other animals and plants, which would in turn cause harm to the people.

This broad definition highlights the main feature of this type of warfare, that it involves living organisms. These micro-organisms include bacteria, viruses and, to a lesser extent, fungi. although there are a vast number of species of these micro-organisms, it is only pathogenic organisms, those capable of causing disease, which are potential agents for biowarfare.

During the late 19th century, pioneering work in bacteriology by scientists such as Pasteur and Koch resulted in the establishment of a 'germ theory' of disease. Where the causes of disease had once been ill defined, scientists now pinned specific micro-organisms to specific diseases. While this change in scientific outlook paved the way for progress in medicine, it also underpinned systematic research into disease as a weapon of war.



botulism (also see botulinum toxin)

Botulism is caused by toxins produced by the bacterium Clostridium botulinum. There are three forms of botulism: foodborne, wound and infant. In all forms, the symptoms include double and blurred vision, drooping eyelids, slurred speech, difficulty swallowing and muscle weakness. The toxins produced by Clostridium can severely damage nerves and muscles leading to paralysis and respiratory failure.

The condition is uncommon and needs hospital treatment. If diagnosed early, an antitoxin can be used to block the action of the toxin.



botulinum toxin (also see botulism)

Botulinum toxin is the poisonous substance produced by the bacterium, Clostridium botulinum, as it grows. It causes the disease botulism which can be fatal.

Once it has entered the body, the botulinum toxin binds to nerve endings and prevents muscles receiving the signals that make them contract. This leads to muscle weakness, paralysis and respiratory failure.



brucellosis

Brucellosis is a bacterial disease that mainly occurs in animals. Many types of animals can be infected including cattle, sheep, goats, pigs, deer and dogs. Humans can become infected by consuming products such as milk and cheese from infected animals as well as by breathing in the Brucella bacteria.

In humans, the symptoms of brucellosis are similar to flu and may cause long-lasting or recurrent fever, joint pain and fatigue. Antibiotics can be used to treat the infection.



BSE (bovine spongiform encephalopathy)

BSE, or 'mad cow disease', is a fatal degenerative disease that affects cattle. The cow's brain gradually becomes 'spongy' as its brain cells are destroyed. BSE was first recognised as a specific disease in 1986 and has been linked with variantCJD, a similar disease in humans.

BSE is caused by prions, abnormal forms of a protein found in the brain and nervous system. When a prion encounters the normal form, it can convert the protein to its abnormal form. As the prions spread they kill brain cells, causing holes to appear throughout the brain.

Cows being fed the remains of infected animals probably caused the initial spread of BSE through the cattle population.



bubonic plague – see plague



bugs

A general term covering bacteria and viruses.

C



cell

A cell is the basic building block of living organisms – all living organisms are made of cells. Single celled organisms exist, but any organism that we can see will be made up of millions of tiny cells.

Cells are made up of one or more compartments filled with a concentrated solution of chemicals.



chain reaction

In nuclear fission [see fission] neutrons are used to bombard an atomic nucleus, causing it to split and release neutrons and energy. These neutrons are then able to collide with other nuclei, causing them in turn to split, releasing further neutrons.

This neutron cascade rapidly produces large amounts of neutrons, and the rate of nuclear fission increases with each collision. Vast amounts of energy are released in a short time – the ideal condition for a bomb. The nuclear reactors used in nuclear power stations slow down the chain reaction and control it, absorbing some of the neutrons. In these reactors the amount of energy released is kept constant.



chemical weapons

Chemical weapons use toxic chemical substances to cause injury or fatality. Various chemicals can be used to cause breathing difficulties, skin damage or damage to the nervous system.



cholera

Cholera is an infection of the small intestine caused by the bacterium Vibrio cholerae. The symptoms of cholera include profuse watery diarrhoea, vomiting, muscle cramps and severe dehydration.

Cholera is spread by drinking water or eating food contaminated with Vibrio bacteria, usually from human faeces. It can spread rapidly in areas with poor sewage treatment.

Cholera can be treated by replacing lost fluids, often by drinking a rehydration solution. Antibiotics can be used to shorten the course and reduce the severity of the illness.



chromosomes

Chromosomes are thread-like structures found within a specific area of the cell known as the nucleus. Each chromosome is an incredibly long strand of DNA, plus some proteins. Chromosomes normally occur in pairs, one half of the pair from each parent – humans have 23 pairs. The exception is in the sex cells, sperm and eggs, which only contain one chromosome from each pair.



clones

Clones are identical individuals that have exactly the same DNA. Asexual reproduction – where a cell from a single parent forms an entirely new individual, identical to the parent – occurs in nature to produce clones. This process is familiar in plants – most gardeners are skilled at propagation, ie producing plant clones.

However, creating clones of mammals in the lab is an incredibly complicated procedure and is also fraught with ethical concerns.



Columbus, Christopher

Christopher Columbus (1451-1506) was an Italian seaman, navigator and explorer. He led four expeditions across the Atlantic to the Americas, alerting Europeans to the continent's existence.

By sailing west around the globe, Columbus hoped to find a new route to China and India. These lands were rich in the herbs, spices, gold and jewels that the Europeans valued, but access via eastern overland routes was difficult. Columbus thought that the eastern edges of these lands were not actually that far west over the Atlantic.

Columbus' journeys were sponsored by the Spanish sovereigns, Ferdinand and Isabella, who saw an opportunity to gain greater power than their arch-rival, Portugal. The first expedition set off in 1492 and explored islands in the Bahamas.



Copernicus, Nikolai

Nikolai Copernicus (1473-1543) was a Polish physician, priest and astronomer. He shattered the established view of the Universe, by declaring that the Sun not the Earth was at its centre.

In the 16th century the model of the Universe was based on the Ptolemaic system, developed in the 2nd century AD. This placed the Earth at the centre of the Universe with the Sun, Moon, planets and stars surrounding the Earth in crystalline spheres. This Earth-centred view was re-enforced by the Church, as it agreed with their teachings.

Copernicus demonstrated that placing the Sun at the centre instead of the Earth solved many problems associated with the motions of the planets.



correlation

Correlation is a statistical measure of the relationship between two associated phenomena. There is a correlation between two phenomena when they tend to occur together or vary in relation to each other in a way that cannot be just down to chance. The correlation coefficient measures the extent to which variations in one phenomenon are related to variations in another.



cortisol

Cortisol is a hormone produced by the adrenal glands. It controls carbohydrate metabolism, helping regulate the formation of glucose.

It's released when the body is subjected to stress such as exercise, fasting, bleeding and infection. The excess cortisol causes the breakdown of proteins contained in muscle tissue. This liberates amino acids that can be used to build new proteins needed elsewhere.



Crusades, The

The crusades were a series of military expeditions launched by Christian Europe against the Muslim occupation of Jerusalem and the Holy Land. Control of this region passed from one side to the other during the period 1095 to 1270. However, the Muslims eventually drove out the crusaders.

As Western Europe gained a level of organisation, wealth and technology unseen since the fall of the Roman Empire, it came into conflict with the expanding Muslim empires to the South and East. Under holy command from the Pope, the nobility stopped attacking each other and united to fight the outside enemy.

Despite noble intentions, many crusades descended into chaos, with financial problems, conflict between rulers, mass slaughters and pillaging. In the Fourth Crusade, crusaders ended up attacking Constantinople, and precipitated the fall of the Eastern Christian Empire.



crystal growth (also see protein crystals)

Crystals can be 'grown' from solution. In the example of protein crystal growth, a solution of a protein is prepared and then the protein molecules are coaxed into crystallising out of the solution.



culture collections (also see American Type Culture Collection)

Culture collections are like library collections of actual micro-organisms or cultured (grown outside of a living organism) cells.

This means that species or strains (variants of the same species) of micro-organisms that are potentially useful to industry or are pathogens can be accessed easily for study.

D



da Vinci, Leonardo

Leonardo da Vinci (1452-1519) was an Italian artist, engineer and scientist whose profound achievements were driven by his love of observation and desire for knowledge, marking him as the epitome of 'Renaissance Man'.

Few completed artistic works by da Vinci survive, but works such as the Mona Lisa and the Last Supper are world famous. His technical and stylistic innovations, including his handling of light and shadow, colour, and the human form, were taken up by later painters.

Investigating the workings of the natural world, da Vinci studied diverse areas, including anatomy, geology, meteorology and hydraulics. However, many of his discoveries did not meet a wide audience, so many ideas were developed anew by later scientists.



de Gama, Vasco

Vasco de Gama (c.1460-1524) was a Portuguese explorer who opened up a new sea route to India, by way of the Cape of Good Hope around the southern tip of Africa.

The Portuguese kings hoped to find a new trade route that would break the Muslim monopoly on trade with India. Europeans valued trade with eastern countries, who held vast resources of herbs, spices and precious metals. But access to these lands was difficult, involving overland travel through hostile regions.

De Gama's first voyage was in 1492. He sailed around the Cape of Good Hope before reaching Mozambique, then finally southern India. although the first expedition was financially unsuccessful, rewarding trade was soon established, swelling Portugal's economic power.



Dee, John

John Dee (1527-1608) was an English mathematician, astrologer and magician. His interest in the magical arts made him a celebrity in Elizabethan England.

Dee was a distinguished mathematician and astrologer who contributed to a English revival of interest in mathematics. However, it was his study of the occult and demonstrations of magic that brought him his fame. He became obsessed with alchemy, conversed with spirits and experienced visions. although imprisoned for a time for being a magician he later gained favour with Elizabeth I, and even cast horoscopes for her.



DNA

DNA is an abbreviation of deoxyribonucleic acid. It contains all the genetic information cells need, and is basically a set of recipes for making proteins. These proteins either form part of the cell itself, or put together structures or molecules needed by the cells.



donor egg

A donor egg is an egg which has been donated for use in vitro fertilisation – the fertilised egg is implanted into the womb of a different woman to the one who donated the eggs. If a woman is infertile because she doesn't have healthy eggs of her own, but she has a healthy womb, she can still carry a child after in vitro fertilisation using a donor egg.



Drake, Sir Francis

Sir Francis Drake (c.1540-1596) was an English seaman, privateer and explorer who circumnavigated the globe.

In the Elizabethan era, England's growing power came up against Spain, the greatest nation of the age. Drake developed a long-term hatred of the Spanish, and became an officially licensed pirate who attacked their ships and ports, gaining great wealth.

In 1577 he set sail on an expedition that took him into the Pacific Ocean and the west coast of South America. Here he raided unguarded Spanish possessions before travelling on to North America. Completing his circumnavigation, he arrived back in England in 1580 both rich and famous.

In 1588 he played a major role in the defeat of the Spanish Armada, making him a hero.



dynamo

A dynamo generates electricity from motion. An electric current is induced in a wire if there is a changing or moving magnetic field. A coil of wire can be spun between the poles of a permanent magnet and this generates a current in the wire. The coil of wire is connected to the circuit by split rings so the wires do not get tangled.