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Phonomyography
Phonomyography (PMG) (also known as acoustic myography, sound myography, vibromyography, and surface mechanomyogram) is a technique to measure the force of muscle contraction by recording the low frequency sounds created during muscular activity. Although, until recently, less precise than the more traditional mechanomyography, it is considerably easier to set up. The signal is measured using condenser microphone elements, piezoelectric sensors, accelerometers, or a combination of sensors attached to the skin. Hydrophones have also been used to measure muscles immersed in water. Improvements in microphones and contact transducers (piezoelectric devices), as well as recording systems, has meant that they have become available in a size and of a quality that enables them to be applied to a normal daily setting outside the clinic and the laboratory setting. These new possibilities provide a clinical tool for the assessment of patients with musculoskeletal complaints during daily a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Mechanomyogram
The mechanomyogram (MMG) is the mechanical signal observable from the surface of a muscle when the muscle is contracted. At the onset of muscle contraction, gross changes in the muscle shape cause a large peak in the MMG. Subsequent vibrations are due to oscillations of the muscle fibres at the resonance frequency of the muscle. The mechanomyogram is also known as the phonomyogram, acoustic myogram, sound myogram, vibromyogram or muscle sound. Signal characteristics The MMG is a low frequency vibration that may be observed when a muscle is contracted using suitable measuring techniques. Measurement techniques It can be measured using an accelerometer or a microphone placed on the skin over the belly of the muscle. When measured using a microphone, it may be termed the acoustic myogram. Uses The MMG may provide a useful alternative to the electromyogram (EMG) for monitoring muscle activity. It has a higher signal-to-noise ratio than the surface EMG and thus can be used to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Piezoelectricity
Piezoelectricity (, ) is the electric charge that accumulates in certain solid materials—such as crystals, certain ceramics, and biological matter such as bone, DNA, and various proteins—in response to applied mechanical stress. The piezoelectric effect results from the linear electromechanical interaction between the mechanical and electrical states in crystalline materials with no inversion symmetry. The piezoelectric effect is a reversible process: materials exhibiting the piezoelectric effect also exhibit the reverse piezoelectric effect, the internal generation of a mechanical strain resulting from an applied electric field. For example, lead zirconate titanate crystals will generate measurable piezoelectricity when their static structure is deformed by about 0.1% of the original dimension. Conversely, those same crystals will change about 0.1% of their static dimension when an external electric field is applied. The inverse piezoelectric effect is used in the pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Francesco Maria Grimaldi
Francesco Maria Grimaldi (2 April 1618 – 28 December 1663) was an Italian Jesuit priest, mathematician and physicist who taught at the Jesuit college in Bologna. He was born in Bologna to Paride Grimaldi and Anna Cattani. Work Between 1640 and 1650, working with Riccioli, he investigated the free fall of objects, confirming that the distance of fall was proportional to the square of the time taken. Grimaldi and Riccioli also made a calculation of gravity at the Earth's surface by recording the oscillations of an accurate pendulum. In astronomy, he built and used instruments to measure lunar mountains as well as the height of clouds, and drew an accurate map or, '' selenograph'', which was published by Riccioli and now adorns the entrance to the National Air and Space Museum in Washington D.C. He discovered and was the first to make accurate observations on the diffraction of light and coined the word 'diffraction'. In his book ''Physico-Mathesis de Lumine, Colori ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Neurophysiology
Neurophysiology is a branch of physiology and neuroscience concerned with the functions of the nervous system and their mechanisms. The term ''neurophysiology'' originates from the Greek word ''νεῦρον'' ("nerve") and ''physiology'' (which is, in turn, derived from the Greek ''φύσις'', meaning "nature", and ''-λογία'', meaning "knowledge"). Neurophysiology has applications in the prevention, diagnosis, and treatment of many neurological and psychiatric diseases. Neurophysiological techniques are also used by clinical neurophysiologists to diagnose and monitor patients with neurological diseases. The field involves all levels of nervous system function, from molecules and cells to systems and whole organisms. Areas of study include: * The electrochemical properties of neurons * Function and regulation of proteins in neurons and glia * Metabolic reactions relevant to neural function * Cell signalling in the nervous system * Neurotransmission and synaptic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Medical Tests
A medical test is a medical procedure performed to screening (medicine), detect, medical diagnosis, diagnose, or monitoring (medicine), monitor diseases, disease processes, susceptibility, or to determine a course of treatment. Medical tests such as, physical and visual exams, diagnostic imaging, genetic testing, chemical and cellular analysis, relating to clinical chemistry and molecular diagnostics, are typically performed in a Medical laboratory, medical setting. Types of tests By purpose Medical tests can be classified by their purposes, including diagnosis, screening or monitoring. Diagnostic A diagnostic test is a procedure performed to confirm or determine the presence of disease in an individual suspected of having a disease, usually following the report of symptoms, or based on other medical test results. This includes posthumous diagnosis. Examples of such tests are: * Using nuclear medicine to examine a patient suspected of having a lymphoma. * Measuring the blood ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Hermann Von Helmholtz
Hermann Ludwig Ferdinand von Helmholtz (; ; 31 August 1821 – 8 September 1894; "von" since 1883) was a German physicist and physician who made significant contributions in several scientific fields, particularly hydrodynamic stability. The Helmholtz Association, the largest German association of research institutions, was named in his honour. In the fields of physiology and psychology, Helmholtz is known for his mathematics concerning the eye, theories of vision, ideas on the visual perception of space, colour vision research, the sensation of tone, perceptions of sound, and empiricism in the physiology of perception. In physics, he is known for his theories on the conservation of energy and on the electrical double layer, work in electrodynamics, chemical thermodynamics, and on a mechanical foundation of thermodynamics. Although credit is shared with Julius von Mayer, James Joule, and Daniel Bernoulli—among others—for the energy conservation principles that e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
René Laennec
René-Théophile-Hyacinthe Laennec (; 17 February 1781 – 13 August 1826) was a French physician and musician. His skill at carving his own wooden flutes led him to invent the stethoscope in 1816, while working at the Hôpital Necker. He pioneered its use in diagnosing various thorax, chest conditions. He became a lecturer at the in 1822 and professor of medicine in 1823. His final appointments were that of head of the medical clinic at the Hôpital de la Charité and professor at the Collège de France. He went into a coma and subsequently died of tuberculosis on 13 August 1826, at age 45. Early life Laennec was born in Quimper, Brittany, Quimper (Brittany). His mother died of tuberculosis when he was five years old, and he went to live with his great-uncle the Abbé Laennec (a priest). As a child, Laennec became ill with fatigue (medical), lassitude and repeated instances of fever, pyrexia. Laennec was also thought to have asthma. At the age of twelve, he proc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Paul Erman
Paul Erman (29 February 1764 – 11 October 1851) was a German physicist from Berlin, Brandenburg and a Huguenot of the fourth generation. His work was mainly concerned with electricity and magnetism, though he also made some contributions to optics and physiology. Life He was the son of the historian Jean Pierre Erman (1735–1814), author of ''Histoire des réfugiés''. Erman became teacher of science successively at the French gymnasium ( Französisches Gymnasium Berlin) in Berlin, and at the military academy, and on the foundation of the University of Berlin in 18 months he was chosen professor of physics. Erman died in Berlin. He had a son, Georg Adolf Erman who was a physicist, and a grandson Johann Peter Adolf Erman, known as an Egyptologist. Awards Erman is one of the three four recipients of the Galvanism Prize awarded by Napoleon Napoleon Bonaparte (born Napoleone di Buonaparte; 15 August 1769 – 5 May 1821), later known by his regnal name Napo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
William Hyde Wollaston
William Hyde Wollaston (; 6 August 1766 – 22 December 1828) was an English chemist and physicist who is famous for discovering the chemical elements palladium and rhodium. He also developed a way to process platinum ore into malleable ingots,Melvyn C. UsselmanWilliam Hyde WollastonEncyclopædia Britannica, retrieved 31 March 2013 patented the camera lucida, and made contributions in electricity and spectroscopy. Life He was born in East Dereham in Norfolk, the son of the Francis Wollaston (1737–1815), a noted amateur astronomer, and his wife Althea Hyde. He was one of 17 children, but the family was financially well-off and he enjoyed an intellectually stimulating environment. He was educated privately (and remotely) at Charterhouse School from 1774 to 1778 then studied Sciences at Gonville and Caius College, Cambridge. In 1793 he obtained his doctorate (MD) in medicine from Cambridge University, and was a Fellow of his college from 1787 to 1828. He worked as a ph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Hertz
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or Cycle per second, cycle) per second. The hertz is an SI derived unit whose formal expression in terms of SI base units is 1/s or s−1, meaning that one hertz is one per second or the Inverse second, reciprocal of one second. It is used only in the case of periodic events. It is named after Heinrich Hertz, Heinrich Rudolf Hertz (1857–1894), the first person to provide conclusive proof of the existence of electromagnetic waves. For high frequencies, the unit is commonly expressed in metric prefix, multiples: kilohertz (kHz), megahertz (MHz), gigahertz (GHz), terahertz (THz). Some of the unit's most common uses are in the description of periodic waveforms and musical tones, particularly those used in radio- and audio-related applications. It is also used to describe the clock speeds at which computers and other electronics are driven. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Muscle
Muscle is a soft tissue, one of the four basic types of animal tissue. There are three types of muscle tissue in vertebrates: skeletal muscle, cardiac muscle, and smooth muscle. Muscle tissue gives skeletal muscles the ability to muscle contraction, contract. Muscle tissue contains special Muscle contraction, contractile proteins called actin and myosin which interact to cause movement. Among many other muscle proteins, present are two regulatory proteins, troponin and tropomyosin. Muscle is formed during embryonic development, in a process known as myogenesis. Skeletal muscle tissue is striated consisting of elongated, multinucleate muscle cells called muscle fibers, and is responsible for movements of the body. Other tissues in skeletal muscle include tendons and perimysium. Smooth and cardiac muscle contract involuntarily, without conscious intervention. These muscle types may be activated both through the interaction of the central nervous system as well as by innervation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Bandpass Filter
A band-pass filter or bandpass filter (BPF) is a device that passes frequencies within a certain range and rejects ( attenuates) frequencies outside that range. It is the inverse of a '' band-stop filter''. Description In electronics and signal processing, a filter is usually a two-port circuit or device which removes frequency components of a signal (an alternating voltage or current). A band-pass filter allows through components in a specified band of frequencies, called its '' passband'' but blocks components with frequencies above or below this band. This contrasts with a high-pass filter, which allows through components with frequencies above a specific frequency, and a low-pass filter, which allows through components with frequencies below a specific frequency. In digital signal processing, in which signals represented by digital numbers are processed by computer programs, a band-pass filter is a computer algorithm that performs the same function. The term ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
