Aflatoxins belong to a group of toxins called mycotoxins, which are derived from fungi. In particular, aflatoxins are produced by the soil-born molds Aspergillus flavus and Aspergillus parasiticus that grow on the seeds and plants. At least 13.... View more

Aflatoxins belong to a group of toxins called mycotoxins, which are derived from fungi. In particular, aflatoxins are produced by the soil-born molds Aspergillus flavus and Aspergillus parasiticus that grow on the seeds and plants. At least 13 aflatoxins have been identified including B1, B2, G1, G2, M1 and M2. The B aflatoxins fluoresce blue and the G aflatoxins fluoresce green in the presence of ultraviolet light. The M aflatoxins are present in milk products. Aflatoxin B1 is the most ubiquitous, most toxic and most well studied of the aflatoxins. Aspergillus spp. contamination occurs as a result of environmental stresses on plants such as heat, dryness, humidity or insect infestation. It can also occur if plants are harvested and stored in hot, humid environments. As a result, people who live in the regions of the world most prone to these conditions, sub-Saharan Africa and southeast Asia are at highest risk for aflatoxin poisoning.

Aflatoxins were first discovered in England in 1960 when more than 10,000 turkeys and ducks died within a few months. The disease contracted by these animals was called Turkey X disease and its cause was traced to Aspergillus flavus contamination of peanut meal that had originated in Brazil. The toxin was named for the short hand of its causative agent: A. fla.

Aflatoxins are the most toxic, naturally occurring carcinogens known. Aflatoxin B1 is an extremely hepatocarcinogenic compound, causing cancer of the liver in humans. Aflatoxin B1 exposure results in both steatosis (an accumulation of fat) and necrosis (cell death) of liver cells. Symptoms of aflatoxicosis are gastrointestinal including vomiting and abdominal pain. Other symptoms can include convulsions, pulmonary edema, coma and eventually death. Aflatoxins also pose a threat to developing fetuses and they are transferred from mother to infant in breast milk. Aflatoxins B1, G1 and M1 are carcinogenic in animals.

Aflatoxin poisoning occurs from ingestion of crops that have been infested with Aspergillus spp. or from eating animal products from animals that have ingested these crops. High concentrations of aflatoxins are most often found in plants with very nutritive seeds such as maize, nuts and cereal grains in Africa and rice in China and Southeast Asia. In the United States, peanuts are routinely tested for aflatoxin concentrations, and contamination has also occurred in corn, rice, and cereal grains.

Most consider aflatoxins extremely dangerous and suggest that in human food is only acceptable with no detectable concentration. The maximum allowable concentration of aflatoxins set by the United States FDA is 20 parts per billion (ppb). Foreign markets usually reject grains with concentrations of 4 to 15 ppb. Acceptable levels of aflatoxins for animal consumption are up to 100 ppb. Because of the strict regulations regarding the permissible concentration of aflatoxin, exporting countries often reserve contaminated grains for consumption within their own country. Because Aspergillus spp. is usually colorless and does not break down during cooking, it is difficult to know whether or not people are consuming contaminated food.

Evidence exists that Iraq used aflatoxins in biological weapons. In December of 1990, Iraq produced 2,200 liters of aflatoxin, 1,580 liters of which were used in biological warheads. In particular, 16 R400 bombs and 2 Al Hussein (SCUD) warheads were filled with the toxin.

The ADFGX cipher, sometimes referred to as the ADFGVX cipher, is one of the most famous codes in the entire history of cryptography. Introduced by the Germans in World War I, it is based on an ancient idea of associating letters with positions on a grid..... View more

The ADFGX cipher, sometimes referred to as the ADFGVX cipher, is one of the most famous codes in the entire history of cryptography. Introduced by the Germans in World War I, it is based on an ancient idea of associating letters with positions on a grid. Variations on the code have made communication possible across the walls of prison cells, and further intricacies added through the technique of transposition have made the code unbreakable without the aid of a computer.

Greek historian Polybius (fl.c. 200 B.C.) introduced what became known as the Polybius square, a 5 x 5 grid that used the 24 letters of the Greek alphabet. Each letter had a unique position identifiable by a coordinate system that numbered the rows and columns. For example, A was one column to the right of the point of origin, and one row down, so its coordinate would be 11. In the English alphabet, two letters are combined in a single square so that the 26 letters fit into the 25-square grid. Supposing I and J are combined, then K would be at position 25—two rows down, and five squares over.

Over the centuries that followed, the Polybius square made possible a system of taps or knocks whereby prisoners could pass messages to one another across walls. Applied by groups ranging from Russian anarchists to American prisoners of war in Vietnam, the system has been described by writers as diverse as Arthur Koestler in Darkness at Noon, Aleksandr Solzhenitsyn in The Gulag

Archipelago, and Senator John S. McCain in Faith of Our Fathers. It has undergone countless variations based on the needs of the users—for example, a 6 x 6 grid for the 33 letters of the Russian alphabet—but the basic principle remains the same. According to the English-language grid described earlier, for instance, K would be rendered by two rapid knocks or taps, a short break, and then five rapid knocks or taps.

The ADFGX Cipher in World War I. The ADFGX cipher, developed by German army radio officer Fritz Nebel (1891–1967), made its appearance on March 5, 1918, when the Germans used it in a wireless transmission on the western front. Instead of the numerals 1 through 5 along a side of the Polybius square, Nebel's cipher applied the letters A, D, F, G, and X, which he chose because their equivalents in Morse code were so dissimilar that confusion was unlikely. (For example, A is one dot and two dashes, while D is one dash and two dots.) Three months later, on June 1, the German army added the letter V to make a sixth row and column. The 6 x 6 grid of the ADFGVX cipher allowed the inclusion of the 10 numerals from 0 to 9, like its predecessor.

The brilliance of the ADFGX cipher lay in the fact that, unlike ordinary codes, the frequency of letters such as E was not easy to recognize. Furthermore, the code could become even more challenging by applying a system of transposition. Suppose a message is written out in ADFGVX format—that is, as a series of two-letter combinations using just those six letters. That string of letters is then placed in a matrix under the letters of a chosen keyword, such as KAISER, which an army in wartime would typically change every day, Then the letters of the keyword are placed in alphabetical order—in this case, spelling AEIKRS, with the corresponding columns moved as well. After being transposed in this manner, the message is transcribed by reading down along each column, making it impossible for anyone who does not know the keyword to translate the message.

A modern computer would be capable of unscrambling such a transmission, even in a situation involving an unknown keyword, but the Allies in World War I were initially unable to break Nebel's code. However, French artillery captain Georges-Jean Painvin (1886–1980) did succeed in deciphering the code. Though his work was good only for a single day, it enabled the allied armies to counter the German offensive of June 9, 1918.

The Abwehr was the German military intelligence organization from 1866 to 1944. The organization predates the emergence of Germany itself, and was founded to gather intelligence information for the Prussian government during a war with neighboring Austria. After.... View more

The Abwehr was the German military intelligence organization from 1866 to 1944. The organization predates the emergence of Germany itself, and was founded to gather intelligence information for the Prussian government during a war with neighboring Austria. After initial successes, the organization was expanded during the Franco-Prussian War in 1870. Under the direction of Wilhelm Stieber, Abwehr located, infiltrated, and reported on French defensive positions and operations. The Prussians claimed victory, largely because of the success of Abwehr agents. In 1871, Prussia united with other independent German states to form the nation of Germany. The new country adopted much of the former Prussian government and military structure, including the Abwehr.

The intelligence agency was again tested at the out-break of World War I in 1914. German agents worked to pinpoint the location and strength of the Allied forces, helping the German forces to invade and progress through northern France before stalemated trench warfare began. New military technology changed the nature of espionage. Agency director Walther Nicolai recognized the need for a modernized intelligence force and reorganized the department to include experts in wire tapping, munitions manufacturing, shipping, and encryption. The agency tapped enemy communications wires, intercepting and deciphering Allied dispatches with measured accomplishment. The Abwehr sent several agents to spy on the manufacture of poison gas in France, and tracked munitions production and shipping in Britain. The organization sent saboteurs to disrupt the shipment of arms from America to Allied forces in Europe. Several ships were sunk in transit after being identified by agents as smuggling arms. German agents, often acting on information collected by Abwehr, set fire to several American weapons factories and storage facilities. While the Abwehr was generally successful, the loss of the German codebook to British intelligence somewhat undermined the agency's ultimate efficacy during the war.

After World War I, the Abwehr ceased operation under the terms of the Versailles Treaty. The intelligence service was re-established in 1921. When the Nazis gained control of Germany in the 1930s, some members of the intelligence agency began to spy on their own government. The Nazis created a separate intelligence organization, the Sicherheitsdienst, or Security Service, headed by Reinhard Heydrich. In 1935, the new Abwehr director, Wilhelm Canaris, and Heydrich reached an agreement about the roles of each agency, but both trained and maintained their own espionage forces. Canaris reorganized the Abwehr into three branches: espionage, counter-espionage, and saboteurs. He appointed three distinguished Abwehr agents to lead the branches, but only on condition that they were not members of the Nazi party. This aroused the suspicion of rival Security Service. The two agencies came into conflict on several occasions, and as Heydrich gained power, he persuaded the government to investigate members of the Abwehr for espionage and treason. Several members of the Abwehr were arrested in 1939. Though a handful of the agency's highest ranking officials were active as double-agents or as members of the Resistance, the organization as a whole continued its espionage operations on behalf of the German government.

At the outbreak of World War II, Abwehr resumed operations similar to those carried out during World War I. The agency was in charge of tracking troops and munitions transports, tapping wires and intercepting radio messages, and infiltrating foreign intelligence and military units. Abwehr placed two operatives inside the British intelligence agency for two years, and developed a highly successful encryption device called the Enigma machine. Agents tracked and monitored various resistance movements in occupied Europe, and even sabotaged military and government strongholds behind Allied lines.

Canaris made the United States one of Abwehr's primary targets even before America's entry into the conflict. By 1942, German agents were operating from within all of America's top armaments manufacturers. Abwehr scored perhaps its greatest victories in the area of industrial espionage, as agents managed to steal the blueprint for every major American airplane produced for the war effort.

One of the Abwehr's responsibilities during World War II was the extraction of information from prisoners of war. While Abwehr agents remained largely in control of seeking strategic information from British, French, and American prisoners, the Nazi government issued a special directive to various branches of the military regarding Russian prisoners of war. The Commissar Order, as it became known, instructed the Army to handle Russian prisoners as harshly as they deemed necessary for the retrieval of military information. At one time, German concentration camps held more that 1.5 million Russian prisoners. Canaris himself raised several objections to this policy, largely on the grounds that it undermined the authority and efficacy of his agency and could cripple the German war effort.

In 1944, Heinrich Himmler, head of the Gestapo, the Nazi secret police, assumed control of Abwehr after an unsuccessful assassination attempt on Adolf Hitler and several other high ranking Nazi officials. Himmler suspected that the plot was the work of agents inside the government, most especially the Abwehr. The July Plot also exposed the work of those Abwehr agents who had intentionally leaked sensitive information to the Allies. Several agents, including Canaris, were charged with treason and executed. The Abwehr was then dissolved.