How will you differentiate between an endo- and an exo- product formation during a diels-alder reaction?
During a Diels-Alder reaction, it is important to look at the diene portion of the reaction. If it is in the cis-form (both alkene are on the same side) as that of a dienophile (both are either in the wedge or the dash form), the product formed will be an Endo form. If it is a trans-form (the alkene are on the opposite side) of the dienophile (one is wedge and the other dash or vice versa) the product formed will be an Exo form.
What is the major cause of Heart Attack?
The cholesterol gets deposited on the walls of the arteries. This causes the lumen (inner wal of the artery) to become narrow in internal dimension. This obstructs the flow of the blood to the other parts of the body that requires it and this can even cause a stroke if the cut-off of blood supply is for a longer duration of time. Over time due to the deposition of the cholesterol on the walls, it may harden up and can rupture. When it ruptures (break open), it forms small blood clots on the surface. The clogging of the blot clots together blocks the flow of the blood from the arteries and due to insufficient blood supply, the heart muscle dies. This leads to heart attack.
What is the history behind the famous painting's of Scream by Edvard Munch and The starry night by Vincent Van Gogh?
Scream by Edvard Munch and The Starry Night by Vincent Van Gogh is among the most famous paintings of all time. Van Gogh painted the starry night in June, 1889. In the foreground, there is a cypress tree which is a representation of a cemetery often associated with mourning. In the distant view, there is a place inspired by Van Gogh's visit to Netherlands. All this is set in a landscape which mimics his view from the window, when he was staying in an asylum at Saint Remy. The sky consists of halo's swirling around the star. He was always a fan of yellow. Historians believed that was due to his intake of digitalis or absinthe. There were reports stating that Van Gogh had a habit of eating paint as he wanted to kill himself. Symptoms of lead poisoning includes Mood disorder, abdominal pain and swelling of the retinas. This might have caused the halo to appear around the light, not unlike a starry night. Scream by Edvard Munch has many versions till date. The famous one was from 1893, using tempera paint on cardboard. The painting is a composite of two perspective on Ekeberg Hill in Oslo, Norway. The background from the foreground is 120 feet above. The screamer, might have been inspired from a Peruvian mummy which was a part of 1889 world's fair in Paris. The sky is blood red. In 1883, there was a volcanic eruption of Krakatoa in the Sunda strait between Java and Sumatra that killed more than 36,000 people. It caused Tsunami whose Remanent were felt till the English channel, the earthquake were detected in Australia and this volcanic activity caused the ash to be shot up in the sky, whose effect lingered for a few years. One of the effect was the color shift in the sky. The sky got darkened. From the East coast of America, all the way till Norway, it became vivid red. And this might be the sunset that Munch saw and depicted in his famous painting.