Saturday, March 21, 2020

Genetic Engineering, history and future Essays - Molecular Biology

Genetic Engineering, history and future Essays - Molecular Biology Genetic Engineering, history and future Altering the Face of Science Science is a creature that continues to evolve at a much higher rate than the beings that gave it birth. The transformation time from tree-shrew, to ape, to human far exceeds the time from analytical engine, to calculator, to computer. But science, in the past, has always remained distant. It has allowed for advances in production, transportation, and even entertainment, but never in history will science be able to so deeply affect our lives as genetic engineering will undoubtedly do. With the birth of this new technology, scientific extremists and anti-technologists have risen in arms to block its budding future. Spreading fear by misinterpretation of facts, they promote their hidden agendas in the halls of the United States congress. Genetic engineering is a safe and powerful tool that will yield unprecedented results, specifically in the field of medicine. It will usher in a world where gene defects, bacterial disease, and even aging are a thing of the past. By understanding genetic engineering and its history, discovering its possibilities, and answering the moral and safety questions it brings forth, the blanket of fear covering this remarkable technical miracle can be lifted. The first step to understanding genetic engineering, and embracing its possibilities for society, is to obtain a rough knowledge base of its history and method. The basis for altering the evolutionary process is dependant on the understanding of how individuals pass on characteristics to their offspring. Genetics achieved its first foothold on the secrets of nature's evolutionary process when an Austrian monk named Gregor Mendel developed the first "laws of heredity." Using these laws, scientists studied the characteristics of organisms for most of the next one hundred years following Mendel's discovery. These early studies concluded that each organism has two sets of character determinants, or genes (Stableford 16). For instance, in regards to eye color, a child could receive one set of genes from his father that were encoded one blue, and the other brown. The same child could also receive two brown genes from his mother. The conclusion for this inheritance would be the child has a three in four chance of having brown eyes, and a one in three chance of having blue eyes (Stableford 16). Genes are transmitted through chromosomes which reside in the nucleus of every living organism's cells. Each chromosome is made up of fine strands of deoxyribonucleic acids, or DNA. The information carried on the DNA determines the cells function within the organism. Sex cells are the only cells that contain a complete DNA map of the organism, therefore, "the structure of a DNA molecule or combination of DNA molecules determines the shape, form, and function of the [organism's] offspring " (Lewin 1). DNA discovery is attributed to the research of three scientists, Francis Crick, Maurice Wilkins, and James Dewey Watson in 1951. They were all later accredited with the Nobel Price in physiology and medicine in 1962 (Lewin 1). "The new science of genetic engineering aims to take a dramatic short cut in the slow process of evolution" (Stableford 25). In essence, scientists aim to remove one gene from an organism's DNA, and place it into the DNA of another organism. This would create a new DNA strand, full of new encoded instructions; a strand that would have taken Mother Nature millions of years of natural selection to develop. Isolating and removing a desired gene from a DNA strand involves many different tools. DNA can be broken up by exposing it to ultra-high-frequency sound waves, but this is an extremely inaccurate way of isolating a desirable DNA section (Stableford 26). A more accurate way of DNA splicing is the use of "restriction enzymes, which are produced by various species of bacteria" (Clarke 1). The restriction enzymes cut the DNA strand at a particular location called a nucleotide base, which makes up a DNA molecule. Now that the desired portion of the DNA is cut out, it can be joined to another strand of DNA by using enzymes called ligases. The final important step in the creation of a new DNA strand is giving it the ability to self-replicate. This can be accomplished by using special pieces of DNA, called vectors, that permit the generation of multiple copies of a total DNA strand and fusing it to the newly created DNA structure. Another newly developed method, called polymerase chain reaction, allows for faster replication of DNA

Wednesday, March 4, 2020

War of 1812 USS Constitution

War of 1812 USS Constitution Shorn of the protection of the Royal Navy, the merchant marine of the young United States began to suffer attacks from North African Barbary pirates in the mid-1780s. In response, President George Washington signed the Naval Act of 1794. This authorized the building of six frigates with the restriction that construction would halt if a peace agreement was reached. Designed by Joshua Humphreys, the construction of the vessels was assigned to various ports on the East Coast. The frigate assigned to Boston was dubbed USS Constitution and was laid down at Edmund Hartts yard on November 1, 1794. Aware that the U.S. Navy would be unable to match the fleets of Britain and France, Humphreys designed his frigates to be able to overpower similar foreign ships but still be fast enough to escape larger ships of the line. Possessing a long keel and narrow beam, Constitutions framing was made of live oak and included diagonal riders which increased the hulls strength and aided in preventing hogging. Heavily planked, Constitutions hull was stronger than similar vessels of its class. Copper bolts and other hardware for the vessel were made by Paul Revere. Key Facts Nation: United StatesBuilder: Edmund Hartts Shipyard, Boston, MALaunched: October 21, 1797Maiden Voyage: July 22, 1798Fate: Museum ship at Boston, MA Specifications of the USS Constitution Ship Type: FrigateDisplacement: 2,200 tonsLength: 175 ft. (waterline)Beam: 43.5 ft.Draft: 21 ft. - 23 ft.Complement: 450Speed: 13 knots Armament 30 x 24-pdrs2 x 24-pdrs (bow chasers)20 x 32-pdr carronades USS Constitution The Quasi-War Though a peace settlement was reached with Algiers in 1796, Washington permitted the three ships nearest completion to be finished. As one of the three, Constitution was launched, with some difficulty, on October 21, 1797. Completed the following year, the frigate readied for service under the command of Captain Samuel Nicholson. Though rated at forty-four guns, Constitution typically mounted around fifty. Putting to sea on July 22, 1798, Constitution began patrols to protect American commerce during the Quasi-War with France. Operating on the East Coast and in the Caribbean, Constitution conducted escort duty and patrolled for French privateers and warships. The highlight of its Quasi-War service came on May 11, 1799 when Constitutions sailors and marines, led by Lieutenant Isaac Hull, seized the French privateer Sandwich near Puerto Plata, Santo Domingo. Continuing its patrols after the conflict ended in 1800, Constitution returned to Boston two years later and was placed in ordinary. This proved brief as the frigate was re-commissioned for service in the First Barbary War in May 1803. USS Constitution and the First Barbary War Commanded by Captain Edward Preble, Constitution arrived at Gibraltar on September 12 and was joined by additional American ships. Crossing to Tangier, Preble exacted a peace treaty before departing on October 14. Overseeing American efforts against the Barbary states, Preble began a blockade of Tripoli and worked to free the crew of USS Philadelphia (36 guns) which had run aground in the harbor on October 31. Unwilling to allow the Tripolitans to keep Philadelphia, Preble dispatched Lieutenant Stephen Decatur on a daring mission which destroyed the frigate on February 16, 1804. Through the summer, Preble mounted attacks against Tripoli with small gunboats and used his frigates to provide fire support. In September, Preble was replaced in overall command by Commodore Samuel Barron. Two months later, he turned command of Constitution over to Captain John Rodgers. Following the American victory at the Battle of Derna in May 1805, a peace treaty with Tripoli was signed aboard Constitution on June 3. The American squadron then moved to Tunis where a similar agreement was obtained. With peace in the region, Constitution remained in the Mediterranean until returning in late 1807. USS Constitution  and the War of 1812 During the winter of 1808, Rodgers supervised a major overhaul of the ship until passing command to Hull, now a captain, in June 1810. After a cruise to Europe in 1811-1812, Constitution was in the Chesapeake Bay when news arrived that the War of 1812 had begun. Departing the bay, Hull sailed north with the goal of joining a squadron that Rodgers was assembling. While off the coast of New Jersey, Constitution was spotted by a group of British warships. Pursued for over two days in light winds, Hull used a variety of tactics, including kedge anchors, to escape. Arriving at Boston, Constitution quickly resupplied before sailing on August 2. Moving northeast, Hull captured three British merchantmen and learned that a British frigate was sailing to the south. Moving to intercept, Constitution encountered HMS Guerriere (38) on August 19. In a sharp fight, Constitution dismasted its opponent and forced it to surrender. During the battle, several of Guerrieres cannon balls were seen to bounce off Constitutions thick sides leading it to earn the nickname Old Ironsides. Returning to port, Hull and his crew were hailed as heroes. On September 8, Captain William Bainbridge took command and Constitution returned to sea. Sailing south with the sloop of war USS Hornet, Bainbridge blockaded the corvette HMS Bonne Citoyenne (20) at Salvador, Brazil. Leaving Hornet to watch the port, he maneuvered offshore seeking prizes. On December 29, Constitution spotted the frigate HMS Java (38). Engaging, Bainbridge captured the British ship after causing its foremast to collapse. Needing repairs, Bainbridge returned to Boston, arriving in February 1813. Requiring an overhaul, Constitution entered the yard and work began under the guidance of Captain Charles Stewart. Sailing for the Caribbean on December 31, Stewart captured five British merchant ships and HMS Pictou (14) before being forced back to port due to issues with the main mast. Pursued north, he ran into Marblehead harbor before slipping down the coast to Boston. Blockaded at Boston until December 1814, Constitution next steered for Bermuda and then Europe. On February 20, 1815, Stewart engaged and captured the sloops of war HMS Cyane (22) and HMS Levant (20). Arriving in Brazil in April, Stewart learned of the wars end and returned to New York. Later Career of the USS Constitution With the end of the war, Constitution was laid up at Boston. Re-commissioned in 1820, it served in the Mediterranean Squadron until 1828. Two years later, an erroneous rumor that the U.S. Navy intended to scrap the ship led to public outrage and caused Oliver Wendell Holmes to pen the poem Old Ironsides. Repeatedly overhauled, Constitution saw service in the Mediterranean and Pacific during the 1830s before embarking on an around the world cruise in 1844-1846. Following a return to the Mediterranean in 1847, Constitution served as flagship of the U.S. African Squadron from 1852 to 1855. Arriving home, the frigate became a training ship at the U.S. Naval Academy from 1860 to 1871 when it was replaced by USS Constellation (22). In 1878-1879, Constitution carried exhibits to Europe for display at the Paris Exposition. Returning, it ultimately was made a receiving ship at Portsmouth, NH. In 1900, the first efforts were made to restore the ship and seven years later it opened for tours. Heavily restored in the early 1920s, Constitution embarked on a national tour in 1931-1934. Further restored several times during the 20th century, Constitution is currently docked at Charlestown, MA as a museum ship. USS Constitution is the oldest commissioned warship in the U.S. Navy.