The term stethoscope is derived from two Greek words; stethos (meaning chest) and scopos (meaning examination). Apart from being used by medical practitioners to hear the heart and chest sounds, the stethoscope is also used to listen to bowel sounds and blood flow noises within the veins and arteries.
The first stethoscope was invented in 1816 by a French physician known as Rene Laennec who used a long, rolled paper tube to funnel the sound. The stethoscope was somewhat simple, but very effective. Three years later, Laennec improved his paper stethoscope into a wooden monaural stethoscope that had a large diameter base that funneled sound through a small opening. But, unlike modern scopes Cheap Amir Johnson Jersey , this early version only transmitted sound to one ear and had ivory ear-tips.
It wasn’t until 1843, that George P. Cammann of New York developed the first binaural (sound into both ears) stethoscope. This is the model that would be used for over 100 years with very few modifications, one of which was the introduction of an ebony chestpiece with tubing made of spirals of wire that was covered in layers of silk dipped in gum elastic. Another modification to the original Cammann stethoscope was done in 1890 when the device was refined with a steel spring between the metal ear tubes.
In 1961, Dr. David Littmann, M.D., (1906-1981) Cheap Jerryd Bayless Jersey , a noted cardiologist, distinguished professor at Harvard Medical School, researcher, inventor, and a recognized international authority on electrocardiography, patented a revolutionary new stethoscope with greatly improved acoustics.
Considered as the most significant milestone in the development of the stethoscope Cheap Darryl Dawkins Jersey , Dr. Littmann’s invention was a streamlined, lightweight stethoscope, with a single tube binaural, which was available in both stainless steel and light alloy.
The device was described by Dr. Littmann, in the November issue of the AMA journal, as the ideal stethoscope. It included a closed chestpiece with a stiff plastic diaphragm to filter-out low-pitched sounds. It also had an open chestpiece to hear low frequency as well as high frequency sounds.
Other innovative features of Dr. Littmann’s stethoscope included firm tubing with a single lumen bore Cheap Charles Barkley Jersey , a spring with precise tension to hold the ear tubes apart with firm and short tubing and had the shortest practical overall length. The device was generally light and convenient to carry and use.
In a bid to promote his invention, Dr. Littmann founded the company Cardiosonics. This company was meant to produce two distinct stethoscopes, one for doctors and another for nurses. On April, 1st 1967, 3M, upon recognizing the acoustics and unique design of the Littmann nurse stethoscopes Cheap Wilt Chamberlain Jersey , decided to acquire Cardiosonics. Dr. Littmann then worked for 3M as an adviser where he helped to further innovate this essential diagnostic tool.
Throughout the years until the late 1970′s, 3M had developed a total of 40 “combination stethoscope” models. The devices were mainly in stainless steel and aluminum featherweight. They had pediatric size, gold-plated chestpieces. The tubing color was still limited to black and grey with lengths of 22 and 28 inches.
It is during this period that the ultimate聽3M Littmann Cardiology Stethoscope聽was born. Commonly known as the “cardiologists’ dream stethoscope” because it was developed by a team of 50 world’s leading cardiologists, this product had a revolutionary two-tubes-in-one design, softer ear-tips and deeper bell for improved response to low frequency. Improvements to the product continued henceforth and in 1987, Tom Packard Cheap Maurice Cheeks Jersey , a 3M engineer, invented the聽3M聽Littmann Master Cardiology Stethoscope, a unique single-sided chestpiece stethoscope which features 3M’s tunable diaphragm technology.
4 Things to Know About Cosmetic Porcelain Veneers Health Articles | January 29, 2017
This article discusses 4 things about getting porcelain veneers and facts about this complicated cosmetic procedure.
As the hub of the Indian arts and entertainment industry, cosmetic medicine is most developed in Mumbai. Services ranging from body etching to cosmetic makeovers are a mainstream part of the extensive industry, and there are many requirements for dental cosmetic procedures. If you want to get porcelain veneers in Mumbai Cheap Julius Erving Jersey , you wouldn't just be popping in at the local dentist! You need an expert who can perform this critical cosmetic procedure flawlessly. Let us learn 4 things about Porcelain Veneers and why they have become so popular -
(a) Understanding The Materials - Porcelain itself is one of the most preferred materials to be used in dentistry. It not only resembles the colour and texture of your natural tooth, but offers a comparable level of hardness. This is why there has been increasing use of porcelain veneers in Mumbai because they have the expected cosmetic effect, as well as prove as a more sustained solution to chipped or broken teeth. Other types of veneers may use both metal and porcelain materials, and there are also crowns made of porcelain to replace teeth entirely!
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