AGRUPAMENTO DE ESCOLAS AUGUSTO CABRITAPortugal – 2015/2016

Major Scientific Events in Europe – 1945 -1968

1949 - LobotomyLobotomy is a surgical procedure in the brain and has been used in the past in severe cases of schizophrenia. About 6 % of patients did not survive the operation, and several others had serious personality disorders. It was developed by the Portuguese doctor Egas Monis which, in 1949, received a Nobel Prize for this contribution to medicine.Starting from the 50’s, lobotomy was banned in most countries, the lobotomy is no longer practiced because of serious side effects, and is considered as one of the most barbaric episodes in the history of psychiatry.

1948 - DDT

(dichlorodiphenyltrichloroethane)

DDT was first synthesized in 1874. It’s colorless, tasteless and nearly odorless.In 1939 Paul Hermann Müller discovered its insecticidal properties. He would later be awarded with the Nobel Prize of medicine, in 1948, due to this discovery.

DDT was largely used in WW2 to control diseases that spread throw insects, such as mosquitoes. It was also used with agricultural applications as an insecticide.In 1962 a biologist published a book where he questioned the environmental impacts of the wide use of DDT, which was mainly in bird communities, and even stated that the usage of several pesticides could lead to cancer in humans. Later, the usage of DDT was banned worldwide on its agricultural applications although the usage of DDT to control diseases is still allowed, in spite being very controversial.

Paul Hermann Müller

António Egas Monis(1874/1955)

DDT molecule

(1899/1965)

1951 Velcro

The Velcro was invented in 1948 by Georges de Mestral, an engineer from Switzerland. He was inspired after analyzing carefully Burdock seeds that constantly stuck in clothes and hair. The material is composed by several intertwined strands ending in small hooks, causing powerful adhesion. Finally he found to be possible to create a material to

join two materials in a reversible and simple wayThe VELCRO name is a reference of two words in French “velours” (meaning velvet) and “crochet” (hook that means).Currently the use and application of the product are different, and the word Velcro has become a generic term to refer to the material which is used to join two rigid surfaces as connection. It is particularly strong because the separating force of the layers is distributed throughout the hooks. Two ways to maximize the strength of the bonding include increasing the connection area and ensure that the separation force is applied parallel to the surface plane of the Velcro.

How Velcro works

1953 - Krebs Cycle

The Krebs cycle, also known as the citric acid cycle, is a series of chemical reactions used to generate energy in eukaryotic cells and some prokaryotic cells (bacteria). In eukaryotic cells, it’s part of a process called aerobic respiration, which occurs in the mitochondria.

The Krebs cycle occurs in the mitochondrial matrix (the fluid part), but it can also occur in prokaryote organisms (organisms that don’t possess mitochondria) in a part of the cell called mesossome. The citric acid cycle was identified in 1937 by Hans Adolf Krebs. He later received the Nobel Prize, in the category of medicine, in 1953.

1953 - Phase-contrast Microscopy

Hans Adolf Krebs(1900/1981) Krebs Cycle

Georges de Menstral(1907/1990)

The same cells imaged with traditional bright-field microscopy (left) and with phase-

contrast microscopy (right)

Phase-contrast Microscopy is a technique used is optical microscopy. It works by converting several light beams, which are passing throw the object, into brightness changes in the images. The light beams themselves are invisible to the naked eye but become visible on the image as brightness changes.When light passes from vacuum to another medium, the wave amplitude, phase and wavelength change, depending of the properties of the medium to which they changed. The absorption and refraction of light makes the changes in amplitude (brightness) appear, and the wavelength changes may even give colour to the images. This technique was created by Frits Zernike (1888/1966) and he was awarded with the Nobel Prize in physics for the invention of the phase contrast microscope in 1953. This device allows the study of the internal structure without the need to stain and thus kill the cells.

1958 - Molecular Structure of Insulin

Frits Zernike(1888/1966)

The determination of the molecular structure of insulin started in 1951 with the determination of two amino acid sequences, part of polypeptide chains in the insulin protein of cows.The most relevant scientist for this discovery was Frederic Sanger. By using a method called partial hydrolysis he was able to determine sequences of many peptides. These sequences would be assembled into longer chains to deduce the complete structure of insulin.Sanger also concluded that two polypeptide chains of protein insulin had precise amino acid sequences and by extension every protein should have as well an unique sequence. This conclusion earned him his Nobel Prize in Chemistry in 1958. This discovery was also very important for the developing theories about how DNA codes proteins.

1962 - Molecular Structure of DNA

Frederic Sanger(1918/2013)

Structure of insulin

The question of how it is possible that instructions are held inside an organism and passed down generation to generation has been asked since the dawn of science. The answer was finally given in 1953 with the publication of an article in the scientific journal Nature, named Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid by Francis Crick and James Watson.This publication described a simple solution, that surprised many biologists, the DNA molecule was responsible for the transmission of the genetic information, and it was configured in the form of a double helix. This discovery was based on the X-ray diffraction (work done by Rosalyn Franklin) and the mathematics of a helix transform.Francis Crick, James Watson and Maurice Wilkings won Nobel Prize for Medicine in 1962 for their discovery of the DNA double helix.

Location of the DNA