Bionics

Bionics

The term "bionics" was coined in 1958 by J. E. STEELE (1924-2009). Bionics describes a branch of science from cybernetics. Living systems have developed their own problem solutions. These are copied or copied and realized or simulated in technical systems constructed by experts. Biology is revolutionizing technology! Machines are transformed into organic systems by new, thought-provoking materials: aircraft are suddenly able to autonomously alter their wing profile, ships can move smoothly like a fish and drive with fin drive, and bridges that have cracks can heal themselves.

The applications extend to all industries, eg. B. on medical technology, design, architecture, information technology, space technology, shipbuilding, railway and automotive. In addition, bionics can help to find ecological solutions at a time when modern technology often reaches environmentally sound limits.

The term bionics was coined in 1958 at a congress in Dayton, Ohio by American Air Force Major J. E. STEELE (1924-2009). He should clarify the "learning from nature for technology". Or, as the German pioneer of bionics, WERNER NACHTIGALL (* 1934), put it: Learning from nature for an independent technical design.

Although the term was new, it only referred to a tried and tested method for centuries. Around the year 1500, the all-rounder LEONARDO DA VINCI (1452-1519) designed a series of flying machines modeled on bird wings and the rotating seeds of the maple tree. However, until a person with wing-like constructions actually rose in the air, it would take around 400 years, because DA VINCI's apparatus was not airworthy. Too much they were still based on a mere imitation of the natural model without consideration of the fundamental laws of physics.

The legend of IKARUS

Had IKARUS, the "flying man" of Greek mythology, known the most important principles of today's bionics, he might not have crashed. Legend has it that his wings, made of feathers and wax, designed exactly on the model of the bird's wing, melted because he came too close to the sun and caused him to fall. And in reality, for many centuries, man's attempts to copy nature were usually doomed to failure. Although there are exceptions such as the plastic sponge or Velcro, which are based on a purely morphological imitation - but they are not the rule.

For WERNER NACHTIGALL, the most renowned German bionic artist, the reason for this is clear: "Nature does not provide any blueprints for the technology. The opinion that one merely needs to copy nature leads to a dead end. "Similarly, the Englishman JULIAN VINCENT puts it this way:" An exact copy of nature would be unwise, because nature is not only incredibly complex, in it also completely different Conditions."

Bionics therefore face the challenge of first understanding which physical principles are behind a successful natural design. If you want to fly like a bird, you first have to analyze why the bird can fly at all. Only then can the knowledge gained be converted into a technical structure. WERNER NACHTIGALL emphasizes: "It is crucial that we approach nature with the know-how of technology and physics and ask the right questions."

And questions about nature are currently booming: not only the classic engineering disciplines such as aircraft and shipbuilding or the architects are looking for suggestions and impulses there, also materials scientists, climate technicians and computer scientists are increasingly oriented to natural role models. Because the constructions of nature are above all one thing: effective with maximum energy and material utilization. In the age of dwindling resources and the threat of climate change, it is above all these characteristics that make nature as a model more interesting than ever.

Bionics describes a branch of science devoted to the comparative analysis of biological and technical systems. It therefore deals with the possibilities of applying biological principles of operation in technology. Technical systems can experience an increase in quality and an extension in general through the results of this science. Of particular interest are biomechanical problems as well as principles of message processing and transmission, and ultimately the energy conversion mechanisms of autotrophic organisms.

Living systems are copied their specially developed solutions to problems and then realized or simulated in resulting constructed technical systems. There are quite a few examples, such as the roofing constructions based on the construction principle of snail shells or the microstructures of diatoms and radiolarians.

Bionics is a science branch of the future that offers scientists countless applications. Researchers are trying to harness the "ways of nature" for economic use in a wide variety of segments. These ingenious technical solutions, modeled on nature, are a promising approach to using limited resources more sparingly and thus ultimately to protect the environment or less burden.

Nature has astonishing solutions for a wide variety of industrial and technical problems. Through her evolutionary inventions of optimized "inventions" she offers design principles of very high efficiency.

Analogies of nature and technology

But even independently, nature and engineers have often developed deceptively similar structures. These analogies are based on the fact that - as in nature itself - certain problems have to be solved under the same or similar conditions.

In the course of millions of years, evolution has ensured that only those constructions and methods survive that can do with a minimum of energy and material. Organisms that developed the most effective methods of food production, reproduction, or locomotion had an advantage over the less effectively "operating" competition and prevailed over the long term.

The process in technology is not much different: inventions and developments are generally accepted by the industry or the free market only if they are connected with the lowest possible costs for energy, production or material. As a result, architects and engineers often reproduced the energy-saving or material-saving design principles of nature without being aware of it - they reinvented the wheel.

One of the best known examples is the roof of the Munich Olympic Stadium, built in 1972 by the architect FREI OTTO (* 1925). The glass and steel construction of the roof is suspended freely on poles; the different curvature of the roof surface gives it despite the light and airy acting great strength. Only later did the engineers realize that nature had already produced a similar construction - the network of dangling spiders suspended between grasses. As with the roof of the stadium, the thin threads of the net only have to withstand the tensile loads, the pressure loads are taken over by the "masts" of the blades of grass.

Even with other lightweight construction methods, the architects seem to have taken visual instruction in nature. Many older railway bridges, such as the bridge over the Scottish Firth of Forth, were constructed in steel construction. Instead of solid stone, braced iron girders bear the weight here. Amazingly, this type of bracing resembles the stiffening inside of many hollow bird bones, especially the pelvis of the ratites. Both the bridge and the basin are designed to withstand high loads with a minimum of material - hence the analogy of form.

Such convergences to nature can be found not only in the architecture, but also in almost every household: So the annular ribs of the vacuum cleaner hose are no coincidence. Their job is to keep the hose open even when it is bent heavily. A normal tube with no ribs bends easily in such a case, thus closing the opening in the interior. In the same way, tracheal insects or aqueducts in the wood are stabilized in nature.

Phenomena of bionics

Conceptions from science fiction novels or films seem to be gradually becoming reality. Thus, certain homes are already able to control their temperature and move in an earthquake so that they do not collapse. Or the newly developed aircraft, which automatically make their wing profile thicker or thinner for take-off and landing, as a result of which the control flaps have become superfluous. Finally, one could mention the ships, which instead of the conventional screws have fin-like constructions that actually allow a freighter to become a racing ship.

Many scientists are enthusiastically working on these living-organic, thought-provoking materials known as "smarties" by "insiders." The model for all these developments is the living nature. Just as animals and humans are able to pass on external stimuli via nerve pathways to the brain, process them there or react with muscle movements to changes in their environment, so too dead materials should behave in the future. It is also intended to create immune systems that are able to heal or repair objects in the event of injury or damage. You need three different materials for this:

     1-) Memory metals,

     2-) Electricity generating crystals ("piezoelectric materials"),

     3-) Deformable gels.

These materials act as artificial sensory organs and muscles, so to speak, and when they are networked with an electron brain, they become, in a sense, alive.

1. The memory metals

The simplest form of so-called memory metals can be found in automatic fuses, which protect the circuits from overload. Two different metals, which expand to different degrees, are combined to form a bimetal (alloy). While at normal room temperature the strip is straight so that the current can flow, it will heat up when there is excessive current flow and one metal will expand more than the other: the strip will begin to curve and the current will be cut off.

A straight wire of nitinol (nickel-titanium alloy) is heated first, then turned into a spiral and even bent into a paperclip. When cooling, the wire stretches again. If it is heated again, it forms into a clamp, the atoms, so to speak, remember the lattice structure "programmed in when heat is applied" and jump back into it. The well-known steel empire Krupp very quickly used the "capabilities of this memory metal". Pipes were assembled in this way and windows could be opened and closed with this mechanism. Yes, even new types of propulsion could be discovered and realized with the help of these memory metals. Finally, memory metals were used in high-tech areas:

     * At 115 ° C, satellite satellites unlock the solar paddles in this way, saving technicians vulnerable and complicated controls;

     * Robots can use this effect to use their articulated and motorless gripper hand;

     * In Japanese research laboratories, there are cars where dents can be blown out with a hair dryer.

2. The piezoelectric materials

As early as 1880, it was discovered that the quartz crystals contained in the sand could turn into small power plants when squeezed together. In the normal state, absolute symmetry prevails in the corresponding crystal lattice of the quartz. All components are in their normal place. However, the charges shift immediately as soon as slight deformation has occurred due to pressure or tension. The surfaces charge electrically opposite each other, an electrical voltage is generated. Lighters spray their sparks this way.

The crystals can also perform a dual function: their current-donating property is reversed. With the addition of electricity, there is a change in volume, this effect is achieved with vibrating loudspeaker membranes of telephone handsets. The piezoelectric substances or "piezos" are thus at the same time sensory organ and muscle: a mechanical impact from the outside is converted into a current surge and they are deformed by an added current impulse. Today instead of quartz ceramics are used. While these piezos can only change their shape from 1% instead of 10% compared to the memory metals, they are extremely fast: in one thousandth of a second, they can flex their biceps many hundreds of times, while the mentioned robot hand for one such power act whole second needed.

3. Deformable gels

The deformable gels are, for. For example, polymers consisting of long molecular chains. Researchers can manipulate these chains, change the temperature, or create electrical or magnetic fields. Contained solvent is absorbed or the chains are literally tangled together. Switching between liquid and solid is nothing special, or you let the substances gel, a rhythmically twitching muscle dances around in alternating electric fields.

Organic valves or filters or artificial hearts are created in this way, shock absorbers can work this way (soft on hard gravel roads, hard on a highway).

It was not until the 1970s that the researchers realized that they had to gather their already acquired knowledge: the cooperation of two hitherto very opposite directions was born: biology and technology finally began to merge.

Today, bionics has become a very exciting field of activity: in the meantime, there are houses that cuddle warmly in the cold and are airy and fresh in the heat. How does this work?

There are model houses in the USA, in Japan and also in Germany. The walls or one should rather say "skins" are made of a sandwich glass, in the middle of which are polymers. The greater the heat of the sun that hits the glass, the more these polymers become entangled. They form a milky mass that repels the sun's rays and - hocus pocus - the windows open by themselves. When it gets cooler again outside, the glass surfaces become transparent again and suck the heat of the sun inside the house. At the same time memory metals on the windows are also active: circlips extend and return springs ensure that the windows are closed again.

Even in the wallpaper, these lovable brownies are at work: they contain innumerable small piezoelectric crystals, which transform the paper on the wall, so to speak, into speakers: One could say that the inhabitants feel like a concert hall when listening to music. Sound waves entering from the outside are sent to sound waves that are equally strong but mirror-inverted so that they cancel each other out. So, if the room is right on the highway, the "Piezo wallpaper" still provides heavenly silence.

The skeleton of these model houses also has extraordinary capabilities: Damage repairs itself. The well-tried concrete has always been very popular with builders because of its light and effortless workmanship. Unfortunately, his susceptibility to corrosion has never really gotten him up in safety fanatics. It seems that remediation has now become obsolete for humans: when pouring the concrete, fine tube systems are now drawn into the masonry, which contain two different active ingredients: calcium nitrate and a resinous solution. The American architect CAROLINE DRY is the inventor of this measure: There is a double fuse. When de-icing salt seeps into the concrete, the hoses are dissolved and the calcium nitrate is released, acting as a shield against the salt. If there are cracks in the concrete structure, the resin reservoirs break open and close the "wound" with the resin that is released. Concrete bridges also benefit from this invention. The Schießbergstraße bridge in Leverkusen can therefore call for help if it is overloaded.

The Japanese are probably the furthest in the development of "intelligent buildings". Many years ago, they began building houses whose skeletons can stretch, bend or turn to counter the frequent earthquake.

Microscope

Microscope

Only with the help of the development of microscopy technology was it possible to make even the smallest structures visible and thus overcome the natural limits of human vision. Without the development of microscopy technology, we would not have been able to achieve today's level of biological knowledge. For example, modern genetic engineering, molecular biology or medicine would be unthinkable without the extreme enlargement of cells, viruses, bacteria or other objects.

The beginnings of microscopy can already be seen in antiquity. Already around 500 BC The Greeks and Romans used magnifying glasses as firing glasses to enlarge objects, but it would be around 2,000 years before the first microscope was developed. Around 1637 ANTONY VAN LEEUWENHOEK (1632-1723) developed one of the first microscopes with which he was already able to study tooth decay, the growth of seeds, fruits, flowers and eyes of various animals.

The microscope is an optical device consisting of two lens systems, the objective and the eyepiece. A distinction is made between the light microscope and the electron microscope.

The principle of a light microscope is that of a thin, illuminated object using the lens, which acts like a converging lens, an enlarged image (image) is generated. This is then considered with the eyepiece (practically a magnifying glass), which enlarges the image even more. With a light microscope, however, a maximum of points with a distance of 0.001 mm can be distinguished (100 times what the human eye is capable of).

Therefore, with a 2,000-fold magnification of the object image, the possibilities of the light microscope are exhausted. Therefore, other options have been considered.

The result was the electron microscope. The French physicist LOUIS DE BROGLIE (1892-1987) sought ways to replace the light. In 1924, he realized that moving electrons have shorter wavelengths than light rays, can be bundled and used to scan extremely thin specimens. The electron microscope was "born". It was built in 1931 by the German ERNST RUSKA (1906-1988). This allowed an enlargement of the object image up to 2,000,000 times. In this way it was z. B. possible to recognize the structure of the finest structures of living things and viruses for the first time.

Structure of a microscope

Figure 2 shows the basic structure of a microscope. The microscope has two lens systems: the lens (objects) facing the lens and the eye facing eyepiece. Both systems act like converging lenses. Often several lenses of different focal lengths are available, which allow a different magnification.

The distance between the lens and the eyepiece is determined by the length of the tube. The tube is nothing more than an opaque tube.

The object is on the stage and illuminated from below. This can be done by a built-in lamp or by daylight, which is reflected by a mirror towards the object.

To get a sharp picture, the distance lens object can be changed using a drive wheel.

Mode of action of a microscope

The mode of action of a microscope can be seen from the ray path: With the objective, which faces the object, an enlarged, inverted, side-reversed and real (real) intermediate image of the object is generated. For this to be the case, the object must be between the single and the double focal length of the lens acting like a converging lens.

This intermediate image is viewed through the eyepiece. Since it is within the simple focal length of the eyepiece, the eyepiece looks like a magnifying glass. In other words, the intermediate image creates an enlarged, upright, right-sided and virtual (apparent) image of the object. This image can be viewed with the eyes and also photographed. It is an enlarged, reversed, page-swapped and virtual image of the object.

Magnification on the microscope

By magnifying the image of the object in two stages, a very large overall magnification of the image can be achieved with a microscope. Has z. For example, if the lens is magnified 40 times and the eyepiece is 8 times magnified, the overall magnification is 40 × 8 = 320

In a light microscope, magnifications of up to about 1,000 are used. If higher image magnifications are necessary, one usually uses electron microscopes.

Rules for handling a microscope

When working with a microscope, you should observe the following rules, which are also a convenient sequence of steps:

1. First place the slide with the object to be examined on the stage so that the object is above the opening! Clamp the slide!

2. To give you an overview of the object to be examined, set the smallest magnification with the nosepiece.

3. Move the lens to near the object by turning the drive wheel. Check from the side so that the lens does not touch the object, otherwise the lens and the object may be damaged.

4. Look through the eyepiece and focus on the subject by slowly increasing or decreasing the object lens distance by turning the drive wheel.

5. If necessary, adjust the brightness using the iris or mirror.

6. Now move the slide with the object on the stage until you have found a spot of the object that can be conveniently viewed.

7. Look closely at the object! Make an overview sketch.

8. Choose a higher magnification and look at the object again! Complete the sketch and label it.

Electron Microscopes

The resolution of a light microscope is limited by the wavelength of the light. In the thirties of the 20th century, electron microscopes were developed to achieve higher resolutions and therefore larger image magnifications. They work with electron beams and allow magnifications up to 500 000. Figure 5 shows the basic structure of such a microscope. The deflection of the electron beam is not done with lenses, but by means of magnetic or electric fields.

The development of such electron microscopes is now so advanced that they can also be used to image individual atomic structures. Figure 6 shows an example of this: the electron micrograph of a photonic crystal can be seen.

Manufacture of micro-preparations

Objects that are to be viewed with a microscope usually only have to be prepared for this purpose. It must be made a micro-preparation. For many dry objects (eg pollen, fish scales, hair, wings of insects) this is easy. They can be placed on a microscope slide without prior processing and examined microscopically. So they make dry preparations from them.

From other objects you make wet preparations. The objects are placed in a drop of water on the slide and covered with a coverslip.
In other objects, such as the elderberry, the cork or the pumpkin and corn stalk, only thin cuts must be made so that light can pass. Only then can these objects be viewed using the microscope.

The dry and moist preparations are fresh preparations. These usually do not last long. By special treatment micro-preparations can be made long lasting. The objects are enclosed in resin or gelatin. Such preparations are then called persistent preparations.

One differentiates between the micro-preparations fresh and long-term preparations. A micro-preparation consists of the slide, the object, often a containment medium (eg water) and a coverslip. If you want to examine all the details of the objects and look closely at them, the objects must be stained. So you need special colorants.

For the preparation of a micro-preparation, some equipment and chemicals are needed. In doing so, certain work steps must be adhered to.

History of Microscopy

Antiquity

As early as 500 BC, the Greeks and Romans used magnifying glasses as firing glasses to magnify objects. The findings of early research in the field of optics held by 1000 Alhazen (actually Ibn Al Haitam 965-1038) and described in the "Thesaurus Opticus" invented by him reading stone.

Middle Ages

Even in the Middle Ages, the development of new devices did not stagnate. In the 13th century, the English monk ROGER BACON (1214-1292) succeeded in grinding glass lenses for spectacles. The art of glass grinding was an important prerequisite for the invention of the microscope. It was fashion at the time to carry a "flea glass". It was a metal tube, the size of a thumb, with a lens at the end.

Around 1590, the Dutch eyewear maker ZACHARIAS JANSSEN (1588-1631) discovered that everything he viewed through two lenses in a row appeared magnified. He developed the composite microscope in this way, but did not pursue his discovery.

GALILEO GALILEI (1564-1642), Italian naturalist, improved the device developed by JANSSEN around 1609 and thus already examined the eyes of insects.

Almost at the same time, JOHANNES KEPLER (1571-1630), a German astronomer, was interested in optics and in 1611 developed the astronomical telescope, which consisted of two converging lenses.

A copy of the instrument developed by JANSSEN came into the possession of CORNELIUS DREBBEL (1572-1633), who studied and improved the instrument. This is how the composite microscopes developed by DREBBEL came into being, which arrived in 1622 in London and Rome.

17th century

In the 17th century, the composite microscope developed rapidly. One of the reasons for this was the many scientific researches and treatises in the field of physics, especially optics. For example, in 1637 the book "Dioptrique" by the philosopher and scientist RENÉ DESCARTES (1596-1650) on the law of refraction and in 1665 the work "Micrographia" by ROBERT HOOKE (1635-1703) was published, in which he published detailed microscopic drawings. In addition, he made his own lenses.

In 1666, ISAAC NEWTON (1643 1727) carried out its famous optical experiments. At that time he considered the achromatization impossible, since in his day the lenses of the microscope always divided the white light into its rainbow colors. Small objects were surrounded by color rings, which made it impossible to recognize minute details. Only about 100 years later, the researchers were able to construct achromatic microscopes.

The Dutch cloth merchant ANTONY VAN LEEUWENHOEK (1632-1723) built a "microscope" around 1637 according to his ideas and examined a variety of things - he observed the structure of seeds, fruits, flowers, eyes of various animals and the circulation of tadpoles, as well sperm. He made a separate microscope for each specimen and was one of the first to accurately record and describe the microscopic objects. He published his notes in scientific letters to the Royal Society of London. In 1683 he amazed the readers by stating that there were more creatures in his mouth than people in the Netherlands. The reason for this claim was the examination of the plaque of an eight-year-old boy. LEEUWENHOEK was the first to discover those living things that we now call bacteria. Since he was the secret of the art of lens-grinding, it was not until the nineteenth century that bacteria were able to be observed when the techniques of microscope construction were better mastered.

In 1669 MARCELLUS MALPIGHI (1628-1694) was the first to use the microscope for systematic biological investigations, and ROBERT HOOKE, an English scientist, discovered with his self-made microscope in 1667 that cork consists of small, separate "boxes" (cells). Thus, HOOKE was the discoverer of the plant cell.

Now the development of the microscope progressed rapidly: 1694 NICOLAAS HARTSOEKER (1654-1725) built the simple microscope with threaded tube, around 1700 CHRISTIAN HUYGENS (1629-1695) developed a two-eyepiece (Huygens eyepiece) with the field lens in front of the image plane of the objective ,

18/19. century

JAMES WILSON (1665-1730), GEORGE ADAMS (1708-1773) u. a. developed the microscopes further. WILSON's circular microscope was still working with reflected light, HERTEL (1683-1743) was already using transmitted-light illumination.

Around 1740, JOHANN NATHANIEL LIEBERKÜHN (1711-1756) reopened DESCARTES 'idea of ​​a concave mirror and constructed solar microscopes.

Around 1770 JAN (1715-1801) and HARMANUS (1738-1809) VAN DEYL built the first achromatic microscope objective.

MATTHIAS JAKOB SCHLEIDEN and THEODOR SCHWANN, German scientists, founded the cell theory: They assumed that cells are the basic building blocks of all plants and animals. A study of nature without microscopic examinations was unthinkable for her. Other scientists said that there was still enough to discover without a microscope. The small workshops continued to improve their microscopes.

ROBERT KOCH (1843-1910), a German bacteriologist, discovered the rod-shaped tubercle bacteria, the causative agents of tuberculosis, a vaccine that was at that time dangerous in 1882 with the help of the microscope.

It emerged companies for the production of mechanical-optical devices, eg. For example, from Carl Zeiss (1816-1888) in 1846 in Jena or the glassworks founded by OTTO SCHOTT (1851-1935) in 1884 for the melting and production of glass.

ERNST ABBE (1840-1905), German physicist, began there to develop the scientific basis for the construction of microscopes. In 1872 he developed the theory of image formation in the microscope. Subsequently, light microscopes were produced, the magnification of which is based on light penetrating from the specimen through two glass lenses, the objective lens and the eyepiece.

A constant improvement in the results of microscopy was also achieved by the invention of histological staining by JOSEPH VON GERLACH in 1855, with whose help, for example, body cells were more visible, and 1893 by the development of Köhler illumination with separate regulation of light field and condenser by AUGUST KÖHLER ( 1866-1948).

20-21. century

In the 20th century, the technology of the light microscope was further developed and overhauled. In 1903 HENRY SIEDENTOPF (1872-1940) and RICHARD ZSIGMONDY (1865-1929) developed the ultramicroscope. In 1925 they received the Nobel Prize for this development. In 1904 her invention was also overhauled and the ultraviolet microscope was made by AUGUST KÖHLER and MORITZ VON ROHR (1868-1940). In 1911 CARL REICHERT (1851-1922) developed the luminescence microscope.

In 1931 ERNST RUSKA (1906-1988) and MAX KNOLL (1897-1969) succeeded in developing the first electron microscope. It works on a similar principle as the light microscope. However, the light beam is replaced by an electron beam and the optical lenses are replaced by electromagnetic lenses. Because of this, the resolution of the electron microscope is much higher than that of the light microscope.

In 1941, FRITS ZERNIKE (1888-1966) invented the phase contrast, with the help of which it is possible to obtain high-contrast images in a light microscope without having to dye them in advance. For this discovery, he received the 1953 Nobel Prize.

In the 21st century, the electron microscopes were then improved and further developed.

Using the so-called scanning tunneling microscope developed in 1981, even atoms can be viewed. The development of the Scanning Tunneling Electron Microscope and similar microscopes has made it possible to view, process or produce in areas of one millionth of a millimeter. Its inventors, GERD BINNIG (* 1947) and HEINRICH ROHRER (* 1933), were awarded the Nobel Prize for Physics in 1986 for their work.

In 1985, WIJNAENDTS VAN RESANDT demonstrated "optical cutting", which makes it possible to obtain a three-dimensional image of the object to be microscoped.

Rh factor

Rh factor

Rhesus factor is an inheritable property of red blood cells (erythrocytes). If the factor is present, it is called Rh-positive (Rh +) blood, it is not Rh-negative (Rh) blood.

The Rhesus factor acts like an antigen, d. that is, in Rh-negative blood, antibodies are formed against the Rhesus factor. Therefore, Rhesus factor plays a crucial role in blood transfusion and pregnancy. Donors and recipients of blood must not only have the same blood group but also the same Rhesus factor. If this is not the case, there are incompatibility reactions that can be fatal.

The rhesus factor

The Rhesus factor is an antigen that is located on the surface of the red blood cells (erythrocytes). The erythrocytes are subdivided into four blood groups A, B, AB and 0 according to specific surface properties.

People whose blood cells have no Rhesus factor are referred to as Rh negative (Rh-). Rh-positive (Rh +) are those people in whom the Rhesus factor can be detected.

Antigens - and thus the Rhesus factor - cause the production of antibodies as soon as they enter a foreign body.

Discovery and meaning of Rhesus factor

The Rhesus factor was discovered in 1940 by KARL LANDSTEINER and ALEXANDER WIENER in Rhesus monkeys. The actual goal of the study was to produce antibodies against rhesus monkey erythrocytes in rabbits and guinea pigs. The scientists discovered that in humans, the same antibodies lead to incompatibility reactions, namely to a clumping (agglutination) of the blood cells.
The Rhesus factor inherits according to Mendelian rules.
Much of the world's population has Rh-positive blood.

The discovery of rhesus factor plays a crucial role in blood transfusions and pregnancies.

In the case of blood transfer, the donor's blood group and Rhesus factor must match the recipient's blood type and Rhesus factor. If this is not the case, the blood clumps up and is thereby destroyed.
Pregnancy poses a risk if the mother is Rh-negative and carries a Rh-positive child. Assuming this is the first pregnancy of the mother, at birth, a greater amount of Rh-positive blood of the baby enters the Rh-negative bloodstream of the mother. As a result, antibodies are produced in the blood of the mother, which destroy the blood of the child. This process is safe for the first child, but there is a risk for all subsequent Rh-positive children. The so-called memory cells in the bloodstream of the mother ensure that in case of a second pregnancy with a Rh-positive child antibodies against the blood of the child can be formed very quickly. The antibodies pass through the placenta into the bloodstream of the child. The consequence is a destruction of the red blood cells of the child and there is a blood disease in the fetus.

The hemoglobin of the agglutinated (clumped) blood cells is degraded and bilirubin is formed. Bilirubin damages the child's brain and leads to yellowing of its skin and tissue (jaundice). In return, the embryo quickly produces large quantities of new blood cells, causing the liver and spleen to swell up considerably. Without an immediate blood exchange with Rh-positive blood, the embryo has no chance of survival and dies. a. of heart failure.

Prevention: Today, prenatal examinations can resolve 99% of all Rh-negative mother and Rh-positive pregnancy problems. In this case, the mother is injected before the formation of antibodies and memory cells, a Rh-positive immunoglobulin. The immunoglobulin removes childish red blood cells as they enter the maternal bloodstream. This can prevent the immune reaction in the mother. This process should be repeated every pregnancy.