The Beginning...
The basis of the research we used for the issue of proteins denaturing in the inner ear was based on an article published by Leslie Chambers and Earl Flosdorf in 1936. In this article was an explanation on their experiment that further proved that proteins do denature from intense sound levels. In the experiment, the egg albumin was placed in an aqueous solution that was then subjected to intense sound waves, which caused the egg albumin to produce a coagulum. They had previously done an experiment on egg albumin denaturation, but not just by sound, but also by heat, alcohol, and different pH leveled solutions. In this experiment, they wanted to test this again, but in different atmospheres, such as nitrogen and hydrogen. They concluded that egg albumin does denature but "only at acoustic intensities
sufficient to promote vigorous cavitation of the solution". Also, the egg albumin only coagulated under the environment with carbon dioxide or oxygen, but not in the nitrogen or hydrogen environments.
After finding the article by Chamber and Flosdorf, we discovered the work of Marcos Sotomayor, which helped us confirm our problem. After finishing his Ph.D., he joined the laboratories of David P. Corey and Rachelle Gaudet to do experimental work as a postdoctoral researcher at Harvard University. There he solved the first X-ray crystal structure of a heterophilic cadherin complex formed by two proteins involved in hereditary deafness and blindness.
Hair cells are mechanoreceptors that transform mechanical stimuli into electrical signals in the inner ear. The tip link bond is essential for hair-cell mechanotransduction but not much is known about it and its relativeness to noise induced hearing loss. When Marcos Sotomayor discovered the tip-links molecular components through x-ray crystallography, he was able to explore the capabilities of it. His research showed us that when the rupture of the bonds between Protocadherin-15 and Cadherin-23 occur from mechanical forces (loud sounds), damage can be done to the stereocilia tip-links. When Cadherin-23 is actually denatured, is it able to be replaced by another Cadherin-23, but it is not known how long that can go on for... potentially leading to noise-induced hearing loss once the Cadherin-23 is not being replaced anymore.
The inspiration that drove us to our S.I.M.P.L.E campaign, and our product of SIM, was lead by Dangerous Decibels. Dangerous Decibels is an awareness program that provides research on noise-induced hearing loss, and offers prevention guides. Primarily the system of JOLENE, which is offers a "research tool to study the beliefs and listening practices regarding personal stereo systems", has provided a basis for this project by spreading awareness of this issue. JOLENE was created by Genna Martin and was constructed using a used fashion mannequin and a sound level meter wired to a silicon ear. She mostly makes appearances at fairs and schools. The JOLENE cookbook is also a resource tool that is downloadable and gives sources for materials, references and an introduction to what JOLENE is about.
sufficient to promote vigorous cavitation of the solution". Also, the egg albumin only coagulated under the environment with carbon dioxide or oxygen, but not in the nitrogen or hydrogen environments.
After finding the article by Chamber and Flosdorf, we discovered the work of Marcos Sotomayor, which helped us confirm our problem. After finishing his Ph.D., he joined the laboratories of David P. Corey and Rachelle Gaudet to do experimental work as a postdoctoral researcher at Harvard University. There he solved the first X-ray crystal structure of a heterophilic cadherin complex formed by two proteins involved in hereditary deafness and blindness.
Hair cells are mechanoreceptors that transform mechanical stimuli into electrical signals in the inner ear. The tip link bond is essential for hair-cell mechanotransduction but not much is known about it and its relativeness to noise induced hearing loss. When Marcos Sotomayor discovered the tip-links molecular components through x-ray crystallography, he was able to explore the capabilities of it. His research showed us that when the rupture of the bonds between Protocadherin-15 and Cadherin-23 occur from mechanical forces (loud sounds), damage can be done to the stereocilia tip-links. When Cadherin-23 is actually denatured, is it able to be replaced by another Cadherin-23, but it is not known how long that can go on for... potentially leading to noise-induced hearing loss once the Cadherin-23 is not being replaced anymore.
The inspiration that drove us to our S.I.M.P.L.E campaign, and our product of SIM, was lead by Dangerous Decibels. Dangerous Decibels is an awareness program that provides research on noise-induced hearing loss, and offers prevention guides. Primarily the system of JOLENE, which is offers a "research tool to study the beliefs and listening practices regarding personal stereo systems", has provided a basis for this project by spreading awareness of this issue. JOLENE was created by Genna Martin and was constructed using a used fashion mannequin and a sound level meter wired to a silicon ear. She mostly makes appearances at fairs and schools. The JOLENE cookbook is also a resource tool that is downloadable and gives sources for materials, references and an introduction to what JOLENE is about.
A Brief Biography of NIHL
Noise Induced Hearing Loss, or NIHL, is caused by exposure to noise over 85 decibels for various amounts of time. It is classified as cochlear, or sensorinueral hearing loss, mainly affecting the cochlea of the inner ear. It affects 2% of the world’s adult population - that’s about 80 million people over the age of 24. As of 2010, about 10 million adults and 5.2 million children in the US were suffering from irreversible NIHL. Thirty million more were exposed to dangerous levels of noise every day. While previously common only in adults through occupational exposure, the advent of personal listening devices, and a public slowly becoming more aware of the risks, has shown that children are at risk for developing NIHL and tinnitus. In an Oregon study of 1,120 fourth grade students, it was found that 94.5% of them were at risk for NIHL.
But studies have not only been conducted in America;
-A Scandinavian study on over five hundred teenage boys found a hearing loss greater than 15 dB in 15% of them.
-A German review of clinical data concluded that one in ten adolescents may have some degree of NIHL due to “leisure time noise.”
-A Chinese study found that of the subjects using “personal listening devices”, 14% of them had a hearing loss of more than 25 dB.
-A French survey found hearing problems in 12% of the general sample and that 66% of the subset that attended rock concerts or used “personal listening devices” more than 7 hours a week had hearing loss.
-A German study of a smaller group had similar results.
-A Swedish study of 55 boys (eight to 20 years old) seeking help for tinnitus, found that the majority had been exposed to excessive noise, mostly from recreational music
This shows a universal, growing issue. Even an Australian study, which concluded that while there was “no widespread hearing loss caused by recreational noise”, teenagers will be at high risk for NIHL by their mid-20s “if recreational habits remain the same.” Because tinnitus is often coupled with the hearing loss, the effect can greatly reduce someone’s quality of life.
Tinnitus is generally classified as a ringing in the ears, though can be anything from buzzing to a sound like ocean waves, according to the American Tinnitus Association. While there are many causes for tinnitus development, a study done in Berlin of 581 patients with chronic tinnitus found that 83% also had noise induced hearing loss. Tinnitus can be temporary, persistent, or even shifting – where the sound may take breaks for short periods of time. In general the sound is distressing and irritating – it can make people anxious. A brain imaging study conducted in the 1990’s supports this by showing in some cases, tinnitus affected patient’s limbic system – the emotional center of the brain.
But studies have not only been conducted in America;
-A Scandinavian study on over five hundred teenage boys found a hearing loss greater than 15 dB in 15% of them.
-A German review of clinical data concluded that one in ten adolescents may have some degree of NIHL due to “leisure time noise.”
-A Chinese study found that of the subjects using “personal listening devices”, 14% of them had a hearing loss of more than 25 dB.
-A French survey found hearing problems in 12% of the general sample and that 66% of the subset that attended rock concerts or used “personal listening devices” more than 7 hours a week had hearing loss.
-A German study of a smaller group had similar results.
-A Swedish study of 55 boys (eight to 20 years old) seeking help for tinnitus, found that the majority had been exposed to excessive noise, mostly from recreational music
This shows a universal, growing issue. Even an Australian study, which concluded that while there was “no widespread hearing loss caused by recreational noise”, teenagers will be at high risk for NIHL by their mid-20s “if recreational habits remain the same.” Because tinnitus is often coupled with the hearing loss, the effect can greatly reduce someone’s quality of life.
Tinnitus is generally classified as a ringing in the ears, though can be anything from buzzing to a sound like ocean waves, according to the American Tinnitus Association. While there are many causes for tinnitus development, a study done in Berlin of 581 patients with chronic tinnitus found that 83% also had noise induced hearing loss. Tinnitus can be temporary, persistent, or even shifting – where the sound may take breaks for short periods of time. In general the sound is distressing and irritating – it can make people anxious. A brain imaging study conducted in the 1990’s supports this by showing in some cases, tinnitus affected patient’s limbic system – the emotional center of the brain.
Proteins
Proteins are one of the four organic compounds essential to life. The other three are lipids, carbohydrates, and nucleic acids. Proteins are made up of amino acid chains. Amino acids consist of an amine group, a carboxyl group and an R group. The R group gives the amino acid its chemical identity - the structure of this is how the amino acids are named. There are twenty different amino acids.
The primary protein structure refers to the exact sequence of amino acids in the protein. The amino acids are chained with multiple peptide bonds - which explains why they are called polypeptide chains (poly= many). Proteins have three layers of structure - primary, secondary, and tertiary. These layers fold together into the protein's main shape. The folds are held together by hydrogen and ionic bonding of the side chains of the amino acids and form alpha helixes grouped into beta sheets.
Proteins are very important in the body and do most of the work in the cell. They help with everything from the structure to the functions and regulations of our body’s tissues and organs. For our project, we are looking at how proteins denature in the hair cells of our ear.
Denaturing is the breaking down of the secondary and tertiary structures in a protein - the primary structure stays intact. It causes the protein to unfold, which can prevent the protein from functioning normally, and sometimes prevents it from functioning at all. Proteins denature when they are heated, when their pH is changed (both acidic and basic), and when they are exposed to high decibels.
The primary protein structure refers to the exact sequence of amino acids in the protein. The amino acids are chained with multiple peptide bonds - which explains why they are called polypeptide chains (poly= many). Proteins have three layers of structure - primary, secondary, and tertiary. These layers fold together into the protein's main shape. The folds are held together by hydrogen and ionic bonding of the side chains of the amino acids and form alpha helixes grouped into beta sheets.
Proteins are very important in the body and do most of the work in the cell. They help with everything from the structure to the functions and regulations of our body’s tissues and organs. For our project, we are looking at how proteins denature in the hair cells of our ear.
Denaturing is the breaking down of the secondary and tertiary structures in a protein - the primary structure stays intact. It causes the protein to unfold, which can prevent the protein from functioning normally, and sometimes prevents it from functioning at all. Proteins denature when they are heated, when their pH is changed (both acidic and basic), and when they are exposed to high decibels.
Stereocilia
Hair cells are made up of multiple strands of stereocilia. These cilia contain cytoplasm and the protein actin. Each hair cell contain about 100 tiny stereocilia. The hair cells are located on the Organ of Corti, a structure in the spiral shaped tube called the cochlea. When sound vibrations enter, the stereocilia respond to the vibrations by swaying back and forth. This movement creates electrical impulses. These electrical impulses are then carried to the brain and processed. This is how brain recognizes sound. Stereocilia are vital for hearing and balance. Sensorineural hearing loss is caused by the damage of the inner ear structure, such as deterioration of hair cells and the impairment of the cochlear structure itself.
Decibels
Decibels are a tenth of a bel, units that measure sound intensity. Research shows that 100dB and over can cause serious damage within an eight hour period. Bels were discovered by Alexander Graham Bell. The Decibel scale is logarithmic - which means 20 dB is not twice as loud as 10 dB, it's 100 times as loud.