Illegal drugs, like heroin and cocaine, are also poisonous to the fetus and can cause many different congenital problems. For example, cocaine use during pregnancy can cause microcephaly (a smaller head size than usual) and problems with the way the fetus's urinary system and genitals grow.
Some medications can also hurt the fetus if its mother takes them while she is pregnant. For example:
Before the 1960s, many countries did not have rules about testing medications for their effects on fetuses. This changed partly because of thalidomide. This medication was given to pregnant women for nausea in the 1950s and 1960s. Between 1956 and 1962, more than 10,000 children in 46 different countries were born with birth defects, like arms and legs that had not grown. Thalidomide had not been tested well enough before it started being prescribed. Now, many countries require more testing before a medication can be said to be safe during pregnancy.
If a woman gets an infection while she is pregnant, sometimes the infection can affect her fetus. The placenta protects the fetus from many different viruses, bacteria, and other pathogens that cause infections. However, some pathogens can get through the placenta and infect the fetus. This is called vertical transmission. Some of these infections can cause birth defects.
Examples of infections that can cause birth defects include:
Some chemicals can cause birth defects, if a pregnant woman is exposed to enough of them. For example:
High levels of ionizing radiation can cause birth defects.
Examples of things that do not cause birth defects include:
Mountain pass
In a group of hills or mountains, a pass is a path for crossing a mountain. It is usually a saddle point between two higher areas. Many of the world's mountain ranges have always made travel difficult so passes have been important throughout history in trade, war and migration.
A pass has the general form of a saddle between two mountains. They are often found just above the source of a river, making a sort of "bridge" over to the headwaters of another river. Passes may be very short, with steep slopes to the top of the pass, or valleys of many kilometers.
Roads and railways have been built through passes. Some high and rugged passes may have tunnels dug underneath to let traffic move faster.
The top of a pass is often the only flat ground in the area so it is often a good site for buildings. For countries whose borders lie on a mountain range, the pass is often part of the border. As well as making travel easy between valleys, passes also provide a route between two mountain tops so it is common for tracks to meet at a pass; this often makes them good routes even when travelling between a summit and the valley floor.
Some of the best known passes are Great St. Bernard Pass at in the Alps, the Khyber Pass at between Afghanistan and Pakistan, and the Khardong La Pass at in Jammu and Kashmir, India.
Albrecht Böttcher
Albrecht Böttcher (born 29 December 1954 in Oberwiesenthal, Saxony, Germany) is a German mathematician. His field of research is functional analysis.
Between 1971 and 1973, Böttcher was in an elite class for mathematics at the Chemnitz University of Technology. In 1973, he won a silver medal at the International Math Olympiad in Moscow. He studied mathematics from 1975 to 1979 in Chemnitz. In 1980, he went to Rostov on Don to study and earned a PhD there in 1984. The topic of his dissertation was "The finite section method for the Wiener-Hopf integral operator". After this he worked as scientist assistance at the university of Chemnitz. Since 1992, he is professor for "harmonic analysis and Operator theory" at the Chemnitz University of Technology.
As of 2012, he is the author of nine books and about 180 papers.
ATI Technologies
ATI Technologies Inc. was a Canadian company known for making graphics processing units and motherboard chipsets. It was founded in 1985 as Array Technology Inc. In 2006, ATI was bought by AMD.
Aromatherapy
Aromatherapy is a type of alternative medicine that uses the part of plants known as essential oils. Some people think that aromatherapy helps to change a person's mind, mood or health but this has not been proven scientifically.
Some essential oils like tea tree do have an anti-microbial effect, so they may be useful for the treatment of infections. Evidence that aromatherapy works in treating disease and other conditions is poor.
The ways of using aromatherapy oils include:
Sodium tellurite
Sodium tellurite is a chemical compound. Its chemical formula is NaTeO. It contains sodium and tellurite ions.
Sodium tellurite is a colorless solid. The tellurite ion can react with water to make sodium hydrogen tellurite, NaHTeO. It dissolves in water easily. It is a weak oxidizing agent (can be reduced to tellurium) and a weak reducing agent (can be oxidized to tellurates). It is part of the process in making tellurium.
It is made by reacting tellurium dioxide with sodium hydroxide, or by heating a telluride in air with sodium carbonate.
Sodium tellurite is used in making tellurium. It is also used to make electroplated nickel corrosion-resistant. It can also be used to add a bluish coating to steel. It can be used to isolate certain types of bacteria that it is not toxic to.
Telluride
Telluride is an ion. Chemical compounds containing this ion are called tellurides. Examples are sodium telluride and hydrogen telluride. The chemical formula is Te. Tellurides are strong reducing agents. Some tellurides are impure, making them weaker reducing agents. Tellurides are the main source of tellurium in the ground. It only exists at very high pH. At lower pH's, hydrogen telluride, HTe, is made. When it is acidic (very low pH), hydrogen telluride gas is made.
Tellurate
Tellurate is an ion. Its chemical formula is TeO or TeO. Chemical compounds having the tellurate ion in them are called tellurates. Tellurates are strong oxidizing agents. They are similar to selenates. Tellurates react with acids to make telluric acid.
An example is sodium tellurate (NaTeO). It is made by reacting telluric acid with sodium hydroxide. It can also be made by oxidizing sodium tellurite. It is similar to sodium selenate.
Hydrogen telluride
Hydrogen telluride, also known as hydrotelluric acid, tellane, or tellurium hydride, is a chemical compound. It is also an acid. Its chemical formula is HTe. It contains hydrogen and telluride ions.
Hydrogen telluride is a toxic reactive gas. It easily decomposes to hydrogen and tellurium. It also burns in air to make tellurium dioxide and water. It has a very bad smell of decayed garlic. It is almost as acidic as phosphoric acid. It reacts with some metals and metal oxides to make tellurides.
It is made by adding a strong acid to a telluride, such as sodium telluride.
Hydrogen telluride does not have many uses because it is very toxic and unstable.
Sodium telluride
Sodium telluride is a chemical compound. Its chemical formula is NaTe. It contains sodium and telluride ions.
It is a white solid when pure. It reacts with air to make a mixture of tellurium and tellurides, which would make gray or purple colors. It eventually turns into sodium carbonate and tellurium when in air. It is a powerful reducing agent. It reacts with strong acids to make hydrogen telluride. It reacts with water to make sodium hydrogen telluride, NaHTe.
Sodium telluride is made by reacting tellurium and sodium in liquid ammonia.
Sodium telluride is used to make organic tellurium compounds. It also can act as a reducing agent.
Tellurium(II) bromide
Tellurium(II) bromide, also known as tellurium dibromide, is a chemical compound. Its chemical formula is TeBr. It contains tellurium and bromide ions. The tellurium is in the +2 oxidation state.
Tellurium(II) bromide is a green brown crystalline solid. It absorbs water from the air.
It is made when tellurium(IV) bromide is heated in air. It can also be made by careful reduction of tellurium(IV) bromide.