SUMMARY / RELATED TOPICS

Golden Gate Bridge

The Golden Gate Bridge is a suspension bridge spanning the Golden Gate, the one-mile-wide strait connecting San Francisco Bay and the Pacific Ocean. The structure links the U. S. city of San Francisco, California—the northern tip of the San Francisco Peninsula—to Marin County, carrying both U. S. Route 101 and California State Route 1 across the strait; the bridge is one of the most internationally recognized symbols of San Francisco and the United States. It was designed by engineer Joseph Strauss in 1917, it has been declared one of the Wonders of the Modern World by the American Society of Civil Engineers. The Frommer's travel guide describes the Golden Gate Bridge as "possibly the most beautiful the most photographed, bridge in the world." At the time of its opening in 1937, it was both the longest and the tallest suspension bridge in the world, with a main span of 4,200 feet and a total height of 746 feet. Before the bridge was built, the only practical short route between San Francisco and what is now Marin County was by boat across a section of San Francisco Bay.

A ferry service began as early as 1820, with a scheduled service beginning in the 1840s for the purpose of transporting water to San Francisco. The Sausalito Land and Ferry Company service, launched in 1867 became the Golden Gate Ferry Company, a Southern Pacific Railroad subsidiary, the largest ferry operation in the world by the late 1920s. Once for railroad passengers and customers only, Southern Pacific's automobile ferries became profitable and important to the regional economy; the ferry crossing between the Hyde Street Pier in San Francisco and Sausalito Ferry Terminal in Marin County took 20 minutes and cost $1.00 per vehicle, a price reduced to compete with the new bridge. The trip from the San Francisco Ferry Building took 27 minutes. Many wanted to build a bridge to connect San Francisco to Marin County. San Francisco was the largest American city still served by ferry boats; because it did not have a permanent link with communities around the bay, the city's growth rate was below the national average.

Many experts said that a bridge could not be built across the 6,700-foot strait, which had strong, swirling tides and currents, with water 372 ft deep at the center of the channel, frequent strong winds. Experts said that ferocious winds and blinding fogs would prevent operation. Although the idea of a bridge spanning the Golden Gate was not new, the proposal that took hold was made in a 1916 San Francisco Bulletin article by former engineering student James Wilkins. San Francisco's City Engineer estimated the cost at $100 million, impractical for the time, he asked bridge engineers. One who responded, Joseph Strauss, was an ambitious engineer and poet who had, for his graduate thesis, designed a 55-mile-long railroad bridge across the Bering Strait. At the time, Strauss had completed some 400 drawbridges—most of which were inland—and nothing on the scale of the new project. Strauss's initial drawings were for a massive cantilever on each side of the strait, connected by a central suspension segment, which Strauss promised could be built for $17 million.

Local authorities agreed to proceed only on the assurance that Strauss would alter the design and accept input from several consulting project experts. A suspension-bridge design was considered the most practical, because of recent advances in metallurgy. Strauss spent more than a decade drumming up support in Northern California; the bridge faced opposition, including litigation, from many sources. The Department of War was concerned; the US Navy feared that a ship collision or sabotage to the bridge could block the entrance to one of its main harbors. Unions demanded guarantees. Southern Pacific Railroad, one of the most powerful business interests in California, opposed the bridge as competition to its ferry fleet and filed a lawsuit against the project, leading to a mass boycott of the ferry service. In May 1924, Colonel Herbert Deakyne held the second hearing on the Bridge on behalf of the Secretary of War in a request to use federal land for construction. Deakyne, on behalf of the Secretary of War, approved the transfer of land needed for the bridge structure and leading roads to the "Bridging the Golden Gate Association" and both San Francisco County and Marin County, pending further bridge plans by Strauss.

Another ally was the fledgling automobile industry, which supported the development of roads and bridges to increase demand for automobiles. The bridge's name was first used when the project was discussed in 1917 by M. M. O'Shaughnessy, city engineer of San Francisco, Strauss; the name became official with the passage of the Golden Gate Bridge and Highway District Act by the state legislature in 1923, creating a special district to design and finance the bridge. San Francisco and most of the counties along the North Coast of California joined the Golden Gate Bridge District, with the exception being Humboldt County, whose residents opposed the bridge's construction and the traffic it would generate. Strauss was chief engineer in charge of overall construction of the bridge project. However, because he had little understanding or experience with cable-suspension designs, responsibility for much of the engineering and architecture fell on other experts. Strauss's initial design proposal was unacceptable from a visual standpoint.

The final graceful suspension design was conce

Rothschildia erycina

Rothschildia erycina, or Rothschild's silk moth, is a moth of the family Saturniidae first described by George Shaw in 1796. It is found from Mexico to Paraguay; the habitat is tropical wet savannah. It is found on altitudes of up to 1,200 meters above sea level; the larvae feed on Ailanthus altissima, Exostema, Antonia, Cenostigma and Dodonaea species. The larval stage lasts about 40 days. Pupation takes place in a large silken cocoon; the pupal stage lasts 3 to 4 weeks. Rothschildia erycina erycina Rothschildia erycina mexicana Draudt, 1929 Rothschildia erycina nigrescens Rothschild, 1907

Enzyme potentiated desensitization

Enzyme potentiated desensitization, is a treatment for allergies developed in the 1960s by Dr. Leonard M. McEwen in the United Kingdom. EPD uses much lower doses of antigens than conventional desensitization treatment paired with the enzyme β-glucuronidase. EPD is approved in the United Kingdom for the treatment of hay fever, food allergy and intolerance and environmental allergies. EPD was developed for the treatment of autoimmune disease by the United Kingdom company Epidyme, owned by Dr. McEwen and had been granted a United Kingdom patent. Despite encouraging results in an experimental model of rheumatoid arthritis, the company was placed into liquidation in April 2010. EPD was available in the United States until 2001, when the Food and Drug Administration revoked approval for an investigative study which it had sanctioned; that study had allowed EPD to be imported into the United States without being licensed. The approval was revoked because the EPD treatments included complex mixtures of allergens that were not allowed under FDA rules.

Since 2001, the FDA has banned importation of EPD for the following reasons: EPD is not licensed. The labeling of the medicine does not contain adequate directions for use. A related treatment, Low Dose Allergens, was developed in the US by Dr. Shrader, being a compounding rather than a drug, is not regulated by the FDA. In addition, LDA uses a different allergen mix for the US environment. However, LDA is considered by many in the field to be a repackaging of EPD that circumvents the FDA guidelines that caused EPD to be revoked; the enzyme beta glucuronidase appears to potentiate the desensitizing effect of a small dose of allergen. The quantities of both are smaller than those occurring in the body, but not so small that they can be regarded as homeopathic. Intradermal injections are used; the treatment takes 3–4 weeks before any effect is seen. For food and environmental allergies and intolerances treatments are given at two monthly intervals at first, but the interval between treatments is lengthened.

Hay fever is treated with two shots of EPD outside the pollen season. The treatment uses dilutions of allergen and enzyme to which T-regulatory lymphocytes are believed to respond by favouring desensitization, or down-regulation, rather than sensitization. Once activated these lymphocytes travel to lymph nodes and reproduce or stimulate similar T-lymphocytes. EPD is considered experimental by some allergists. However, there is evidence for the efficacy of EPD in the treatment of hay fever and other conditions as a result of nine placebo-controlled, double-blind trials involving 271 patients; these trials showed a significant improvement in the symptoms with probabilities of 0.001 to 0.01. However, one trial involving 183 patients published in the British Medical Journal showed no overall effect. Dr Len McEwen, inventor of EPD, speculated that the reason for the failure might have been that the beta glucuronidase enzyme preparation was inadvertently heated or frozen during storage in the hospital pharmacy, as it is sensitive to the storage temperature and enzyme from the same manufactured batch had been used to treat a number of patients successfully.

However, there is no evidence available after the event to test this theory as the remaining trial materials were destroyed after the trial ended. While the efficacy of EPD is sometimes the subject of controversy among the medical community, the safety of EPD is demonstrated in one study under the control of an Investigational Review Board and reported by the American EPD Society. 5,400 patients received at least 3 doses of EPD with no severe reactions reported. By contrast uncontrolled use of conventional immunotherapy for general allergic conditions was believed to be responsible for at least 29 deaths in the UK, is now banned in the United Kingdom except in hospital under close observation. A working party of the British Society for Allergy and Clinical Immunology reviewed the role of conventional high dose specific allergen immunotherapy in the treatment of allergic disease and recommends high dose specific allergen immunotherapy for treating summer hay fever uncontrolled by conventional medication and for wasp and bee venom hypersensitivity.

For the recommended indications the risk:benefit ratio was found to be acceptable for conventional immunotherapy provided patients are selected. Conventional escalating-dose immunotherapy has been used to treat tens of millions of people in the United States with appropriate medical supervision with a death rate of less than one in one million according to the American Academy of Allergy and Immunology. EPD has not been developed for treatment of allergy to insect stings, nor for contact dermatitis and allergy to drugs, it is not FDA approved