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Air Displacement Plethysmography
Air displacement plethysmography (ADP, also known as whole-body air displacement plethysmography) is a recognized and scientifically validated densitometric method to measure human body composition. ADP is based on the same principles as the gold standard method of hydrostatic weighing, but through a densitometric technique that uses air displacement rather than water immersion. Air-displacement plethysmography offers several advantages over established reference methods, including a quick, comfortable, automated, noninvasive, and safe measurement process, and accommodates various subject types (e.g., children, obese, elderly, and disabled persons). History The principles of plethysmography were first applied to the measurement of the body volume and composition of infants in the early 1900s, but it was not until the 1960s that relatively stable measurements were achieved. However, these systems required that ambient conditions be maintained constant. Applications in humans have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adult Body Composition Through Air Displacement Plethysmography
An adult is an animal that has reached Developmental biology, full growth. The biological definition of the word means an animal reaching sexual maturity and thus capable of reproduction. In the human context, the term ''adult'' has meanings associated with social and law, legal concepts. In contrast to a non-adult or "minor (law), minor", a legal adult is a person who has attained the age of majority and is therefore regarded as independent, self-sufficient, and :wikt:responsible, responsible. They may also be regarded as "majors". The typical age of attaining legal adulthood is 18 although definition may vary by legal rights, country, and psychological development. Human adulthood encompasses Adult development, psychological adult development. Definitions of adulthood are often inconsistent and contradictory; a person may be biologically an adult, and have adult behavior, but still be treated as a child if they are under the legal age of majority. Conversely, one may legally be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infant Body Composition Through Air Displacement Plethysmography
In common terminology, a baby is the very young offspring of adult human beings, while infant (from the Latin word ''infans'', meaning 'baby' or 'child') is a formal or specialised synonym. The terms may also be used to refer to juveniles of other organisms. A newborn is, in colloquial use, a baby who is only hours, days, or weeks old; while in medical contexts, a newborn or neonate (from Latin, ''neonatus'', newborn) is an infant in the first 28 days after birth (the term applies to premature, full term, and postmature infants). Infants born prior to 37 weeks of gestation are called "premature", those born between 39 and 40 weeks are "full term", those born through 41 weeks are "late term", and anything beyond 42 weeks is considered "post term". Before birth, the offspring is called a fetus. The term ''infant'' is typically applied to very young children under one year of age; however, definitions may vary and may include children up to two years of age. When a human child ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Body Composition
In physical fitness, body composition refers to quantifying the different components (or "compartments") of a human body. The selection of compartments varies by model but may include fat, bone, water, and muscle. Two people of the same gender, height, and body weight may have completely different body types as a consequence of having different body compositions. This may be explained by a person having low or high body fat, dense muscles, or big bones. Compartment models Body composition models typically use between 2 and 6 compartments to describe the body. Common models include: * 2 compartment: Fat mass (FM) and fat-free mass (FFM) * 3 compartment: Fat mass (FM), water, and fat-free dry mass * 4 compartment: Fat mass (FM), water, protein, and mineral * 5 compartment: Fat mass (FM), water, protein, bone mineral content, and non-osseous mineral content * 6 compartment: Fat mass (FM), water, protein, bone mineral content, non-osseous mineral content, and glycogen As a rule, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrostatic Weighing
Hydrostatic weighing, also referred to as underwater weighing, hydrostatic body composition analysis and hydrodensitometry, is a technique for measuring the density of a living person's body. It is a direct application of Archimedes' principle, that an object displaces its own volume of water. Method The procedure, pioneered by Behnke, Feen and Welham as means to later quantify the relation between specific gravity and the fat content, is based on Archimedes' principle, which states that: ''The buoyant force which water exerts on an immersed object is equal to the weight of water that the object displaces.'' Example 1: If a block of solid stone weighs 3 kilograms on dry land and 2 kilogram when immersed in a tub of water, then it has displaced 1 kilogram of water. Since 1 liter of water weighs 1 kilogram (at 4 °C), it follows that the volume of the block is 1 liter and the density (mass/volume) of the stone is 3 kilograms/liter. Example 2: Consider a larger block o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boyle's Law
Boyle's law, also referred to as the Boyle–Mariotte law or Mariotte's law (especially in France), is an empirical gas laws, gas law that describes the relationship between pressure and volume of a confined gas. Boyle's law has been stated as: The absolute pressure exerted by a given mass of an ideal gas is inversely proportional to the volume it occupies if the temperature and amount of substance, amount of gas remain unchanged within a closed system.Levine (1978) p. 12 gives the original definition. Mathematically, Boyle's law can be stated as: or where is the pressure of the gas, is the volume of the gas, and is a Constant (mathematics), constant for a particular temperature and amount of gas. Boyle's law states that when the temperature of a given mass of confined gas is constant, the product of its pressure and volume is also constant. When comparing the same substance under two different sets of conditions, the law can be expressed as: P_1 V_1 = P_2 V_2. showi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrostatic Weighing
Hydrostatic weighing, also referred to as underwater weighing, hydrostatic body composition analysis and hydrodensitometry, is a technique for measuring the density of a living person's body. It is a direct application of Archimedes' principle, that an object displaces its own volume of water. Method The procedure, pioneered by Behnke, Feen and Welham as means to later quantify the relation between specific gravity and the fat content, is based on Archimedes' principle, which states that: ''The buoyant force which water exerts on an immersed object is equal to the weight of water that the object displaces.'' Example 1: If a block of solid stone weighs 3 kilograms on dry land and 2 kilogram when immersed in a tub of water, then it has displaced 1 kilogram of water. Since 1 liter of water weighs 1 kilogram (at 4 °C), it follows that the volume of the block is 1 liter and the density (mass/volume) of the stone is 3 kilograms/liter. Example 2: Consider a larger block o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dual-energy X-ray Absorptiometry
Dual-energy X-ray absorptiometry (DXA, or DEXA) is a means of measuring bone mineral density (BMD) with Spectral imaging (radiography), spectral imaging. Two X-ray beams, with different energy levels, are aimed at the patient's bones. When soft tissue absorption is subtracted, the bone density, bone mineral density (BMD) can be determined from the absorption of each beam by bone. Dual-energy X-ray absorptiometry is the most widely used and most thoroughly studied bone density measurement technology. The DXA scan is typically used to diagnose and follow osteoporosis, as contrasted to the nuclear bone scan, which is sensitive to certain metabolic diseases of bones in which bones are trying to heal from infections, fractures, or tumors. It is also sometimes used to assess body composition. Physics Soft tissue and bone have different Attenuation, attenuation coefficients to X-rays. A single X-ray beam passing through the body is attenuated by both soft tissue and bone, and it is not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isotope Dilution
Isotope dilution analysis is a method of determining the quantity of chemical substances. In its most simple conception, the method of isotope dilution comprises the addition of known amounts of isotopically enriched substance to the analyzed sample. Mixing of the isotopic standard with the sample effectively "dilutes" the isotopic enrichment of the standard and this forms the basis for the isotope dilution method. Isotope dilution is classified as a method of internal standardisation, because the standard (isotopically enriched form of analyte) is added directly to the sample. In addition, unlike traditional analytical methods which rely on signal intensity, isotope dilution employs signal ratios. Owing to both of these advantages, the method of isotope dilution is regarded among chemistry measurement methods of the highest metrological standing. Isotopes are variants of a particular chemical element which differ in neutron number. All isotopes of a given element have the same nu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potassium
Potassium is a chemical element; it has Symbol (chemistry), symbol K (from Neo-Latin ) and atomic number19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to form flaky white potassium peroxide in only seconds of exposure. It was first isolated from potash, the ashes of plants, from which its name derives. In the periodic table, potassium is one of the alkali metals, all of which have a single valence electron in the outer electron shell, which is easily removed to create cation, an ion with a positive charge (which combines with anions to form salts). In nature, potassium occurs only in ionic salts. Elemental potassium reacts vigorously with water, generating sufficient heat to ignite hydrogen emitted in the reaction, and burning with a lilac-flame color, colored flame. It is found dissolved in seawater (which is 0.04% potassium by weight), and occurs in many minerals such as orthoclase, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multi-compartment Model
A multi-compartment model is a type of mathematical model used for describing the way materials or energies are transmitted among the ''compartments'' of a system. Sometimes, the physical system that we try to model in equations is too complex, so it is much easier to discretize the problem and reduce the number of parameters. Each compartment is assumed to be a homogeneous entity within which the entities being modeled are equivalent. A multi-compartment model is classified as a lumped parameters model. Similar to more general mathematical models, multi-compartment models can treat variables as continuous, such as a differential equation, or as discrete, such as a Markov chain. Depending on the system being modeled, they can be treated as stochastic or deterministic. Multi-compartment models are used in many fields including pharmacokinetics, epidemiology, biomedicine, systems theory, complexity theory, engineering, physics, information science and social science. The circ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deuterium
Deuterium (hydrogen-2, symbol H or D, also known as heavy hydrogen) is one of two stable isotopes of hydrogen; the other is protium, or hydrogen-1, H. The deuterium nucleus (deuteron) contains one proton and one neutron, whereas the far more common H has no neutrons. The name ''deuterium'' comes from Greek '' deuteros'', meaning "second". American chemist Harold Urey discovered deuterium in 1931. Urey and others produced samples of heavy water in which the H had been highly concentrated. The discovery of deuterium won Urey a Nobel Prize in 1934. Nearly all deuterium found in nature was synthesized in the Big Bang 13.8 billion years ago, forming the primordial ratio of H to H (~26 deuterium nuclei per 10 hydrogen nuclei). Deuterium is subsequently produced by the slow stellar proton–proton chain, but rapidly destroyed by exothermic fusion reactions. The deuterium–deuterium reaction has the second-lowest energy threshold, and is the most astrophysically acce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Self-care
Self-care has been defined as the process of establishing behaviors to ensure holistic well-being of oneself, to promote health, and actively manage illness when it occurs. Individuals engage in some form of self-care daily with food choices, exercise, sleep, and hygiene. Self-care is not only a solo activity, as the community—a group that supports the person performing self-care—overall plays a role in access to, implementation of, and success of self-care activities. Routine self-care is important when someone is not experiencing any symptoms of illness, but self-care becomes essential when illness occurs. General benefits of routine self-care include Preventive healthcare, prevention of illness, improved mental health, and comparatively better quality of life. Self-care practices vary from individual to individual. Self-care is seen as a partial solution to the global rise in health care costs that is placed on governments worldwide. A lack of self-care in terms of pers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
