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Spaceflight Osteopenia
Spaceflight osteopenia refers to the characteristic bone loss that occurs during spaceflight. Astronauts lose an average of more than 1% bone mass per month spent in space. There is concern that during long-duration flights, excessive bone loss and the associated increase in serum calcium ion levels will interfere with execution of mission tasks and result in irreversible skeletal damage. History Bone loss has been observed during spaceflight since at least as early as Gemini in the 1960s. Although most early measurements of the amount of bone loss were not reliable, they did show bone loss in Gemini, Soyuz 9, Apollo, Skylab, Salyut 7, Mir, and the International Space Station. William E. Thornton, an astronaut and physician, was one of the biggest proponents of exercise as a way of preventing bone loss. Cause Bone remodels in response to stress in order to maintain constant strain energy per bone mass throughout. To do this, it grows more dense in areas experiencing high str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osteoporosis
Osteoporosis is a systemic skeletal disorder characterized by low bone mass, micro-architectural deterioration of bone tissue leading to bone fragility, and consequent increase in fracture risk. It is the most common reason for a broken bone among the elderly. Bones that commonly break include the vertebrae in the spine, the bones of the forearm, and the hip. Until a broken bone occurs there are typically no symptoms. Bones may weaken to such a degree that a break may occur with minor stress or spontaneously. After the broken bone heals, the person may have chronic pain and a decreased ability to carry out normal activities. Osteoporosis may be due to lower-than-normal maximum bone mass and greater-than-normal bone loss. Bone loss increases after the menopause due to lower levels of estrogen, and after ' andropause' due to lower levels of testosterone. Osteoporosis may also occur due to a number of diseases or treatments, including alcoholism, anorexia, hyperthyroidism, k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osteoporosis
Osteoporosis is a systemic skeletal disorder characterized by low bone mass, micro-architectural deterioration of bone tissue leading to bone fragility, and consequent increase in fracture risk. It is the most common reason for a broken bone among the elderly. Bones that commonly break include the vertebrae in the spine, the bones of the forearm, and the hip. Until a broken bone occurs there are typically no symptoms. Bones may weaken to such a degree that a break may occur with minor stress or spontaneously. After the broken bone heals, the person may have chronic pain and a decreased ability to carry out normal activities. Osteoporosis may be due to lower-than-normal maximum bone mass and greater-than-normal bone loss. Bone loss increases after the menopause due to lower levels of estrogen, and after ' andropause' due to lower levels of testosterone. Osteoporosis may also occur due to a number of diseases or treatments, including alcoholism, anorexia, hyperthyroidism, k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Hazards
Space is the boundless three-dimensional extent in which objects and events have relative position and direction. In classical physics, physical space is often conceived in three linear dimensions, although modern physicists usually consider it, with time, to be part of a boundless four-dimensional continuum known as spacetime. The concept of space is considered to be of fundamental importance to an understanding of the physical universe. However, disagreement continues between philosophers over whether it is itself an entity, a relationship between entities, or part of a conceptual framework. Debates concerning the nature, essence and the mode of existence of space date back to antiquity; namely, to treatises like the ''Timaeus'' of Plato, or Socrates in his reflections on what the Greeks called ''khôra'' (i.e. "space"), or in the ''Physics'' of Aristotle (Book IV, Delta) in the definition of ''topos'' (i.e. place), or in the later "geometrical conception of place" a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Timeline Of Longest Spaceflights
Timeline of longest spaceflights is a chronology of the longest spaceflights. Many of the first flights set records measured in hours and days, the space station missions of the 1970s and 1980s pushed this to weeks and months, and by the 1990s the record was pushed to over a year and has remained there into the 21st century. A modern long-duration mission was the ISS year long mission (2015–2016) aboard the International Space Station. The most significant issue in such missions is the effects of spaceflight on the human body, due to such factors as zero-g and elevated radiation. Record setting single-mission human stays References See also * List of spaceflight records * Manned Venus Flyby * Skylab 4 {{Spaceflight lists and timelines Human spaceflight Spaceflight timelines Longest-duration things, Spaceflights ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reduced-gravity Aircraft
A reduced-gravity aircraft is a type of fixed-wing aircraft that provides brief near-weightless environments for training astronauts, conducting research and making gravity-free movie shots. Versions of such airplanes were operated by the NASA Reduced Gravity Research Program, and one is currently operated by the Human Spaceflight and Robotic Exploration Programmes of the European Space Agency. The unofficial nickname "vomit comet" became popular among those who experienced their operation. History Parabolic flight as a way of simulating weightlessness was first proposed by the German aerospace engineer Fritz Haber and the German physicist Heinz Haber in 1950. Both had been brought to the US after World War II as part of Operation Paperclip. As well, Shih-Chun Wang studied nausea in astronauts for NASA, which helped lead to the creation of the vomit comet. Parabolic flights are sometimes used to examine the effects of weightlessness on a living organism. While humans are b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microgravity University
{{primary sources, date=December 2011 Microgravity University, also known as the Reduced Gravity Student Flight Opportunities Program (RGSFOP) was a program run by NASA which enables undergraduate university students to perform microgravity experiments aboard NASA's reduced-gravity DC-9 aircraft at Johnson Space Center in Houston, Texas. Acceptance into the program requires a team of four fliers (and any number of ground crew) and was done through the writing and submission (during late Fall) of a technical proposal which details among other things what the experiment was about, safety considerations, and outreach plans. In the 2007 campaign, 36 of the 74 proposals submitted were accepted. Upon acceptance, a flight date was assigned and the team must design and build the planned experiment by then. Prior to flight, submission of a TEDP (an in-depth description of apparatus) was also required, as were FAA approved physical examinations for all fliers and the optional alternate fli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Adaptation Syndrome
Space adaptation syndrome (SAS) or space sickness is a condition experienced by as many as half of all space travelers during their adaptation to weightlessness once in orbit. It is the opposite of terrestrial motion sickness since it occurs when the environment and the person appear visually to be in motion relative to one another even though there is no corresponding sensation of bodily movement originating from the vestibular system. Presentation Space motion sickness can lead to degraded astronaut performance. SMS threatens operational requirements, reduces situational awareness, and threatens the safety of those exposed to micro-g environments. Lost muscle mass leads to difficulty with movement, especially when astronauts return to earth. This can pose a safety issue if the need for emergency egress were to arise. Loss of muscle power makes it extremely difficult, if not impossible, for astronauts to climb through emergency egress hatches or create unconventional exit sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Medicine
Space medicine is the practice of medicine on astronauts in outer space whereas astronautical hygiene is the application of science and technology to the prevention or control of exposure to the hazards that may cause astronaut ill health. Both these sciences work together to ensure that astronauts work in a safe environment. The main objective is to discover how well and for how long people can survive the extreme conditions in space, and how fast they can adapt to the Earth's environment after returning from their voyage. Medical consequences such as possible blindness and bone loss have been associated with human spaceflight. In October 2015, the NASA Office of Inspector General issued a health hazards report related to space exploration, including a human mission to Mars. History Hubertus Strughold (1898–1987), a former Nazi physician and physiologist, was brought to the United States after World War II as part of Operation Paperclip. He first coined the term "spa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Effect Of Spaceflight On The Human Body
Venturing into the environment of space can have negative effects on the human body. Significant adverse effects of long-term weightlessness include muscle atrophy and deterioration of the skeleton ( spaceflight osteopenia). Other significant effects include a slowing of cardiovascular system functions, decreased production of red blood cells (space anemia), balance disorders, eyesight disorders and changes in the immune system. Additional symptoms include fluid redistribution (causing the " moon-face" appearance typical in pictures of astronauts experiencing weightlessness), loss of body mass, nasal congestion, sleep disturbance, and excess flatulence. Overall, NASA refers to the various deleterious effects of spaceflight on the human body by the acronym RIDGE (i.e., "space radiation, isolation and confinement, distance from Earth, gravity fields, and hostile and closed environments"). The engineering problems associated with leaving Earth and developing space propulsion sys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artificial Gravity
Artificial gravity is the creation of an inertial force that mimics the effects of a gravitational force, usually by rotation. Artificial gravity, or rotational gravity, is thus the appearance of a centrifugal force in a rotating frame of reference (the transmission of centripetal acceleration via normal force in the non-rotating frame of reference), as opposed to the force experienced in linear acceleration, which by the equivalence principle is indistinguishable from gravity. In a more general sense, "artificial gravity" may also refer to the effect of linear acceleration, e.g. by means of a rocket engine. Rotational simulated gravity has been used in simulations to help astronauts train for extreme conditions. Rotational simulated gravity has been proposed as a solution in human spaceflight to the adverse health effects caused by prolonged weightlessness. However, there are no current practical outer space applications of artificial gravity for humans due to concerns ab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Teriparatide
Teriparatide, sold under the brand name Forteo, is a form of parathyroid hormone (PTH) consisting of the first ( N-terminus) 34 amino acids, which is the bioactive portion of the hormone. It is an effective anabolic (promoting bone formation) agent used in the treatment of some forms of osteoporosis. It is also occasionally used off-label to speed fracture healing. Teriparatide is identical to a portion of human parathyroid hormone and intermittent use activates osteoblasts more than osteoclasts, which leads to an overall increase in bone. Medical uses It is effective in growing bone (e.g., 8% increase in bone density in the spine after one year) and reducing the risk of fragility fractures. When studied, teriparatide only showed bone mineral density (BMD) improvement during the first 18 months of use. Teriparatide should only be used for a period of 2 years maximum. After 2 years, another agent such a bisphosphonate or denosumab should be used in cases of osteoporosis althoug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bisphosphonate
Bisphosphonates are a class of drugs that prevent the loss of bone density, used to treat osteoporosis and similar diseases. They are the most commonly prescribed drugs used to treat osteoporosis. They are called bisphosphonates because they have two phosphonate () groups. They are thus also called diphosphonates ('' bis-'' or '' di-'' + '' phosphonate''). Evidence shows that they reduce the risk of fracture in post-menopausal women with osteoporosis. Bone tissue undergoes constant remodeling and is kept in balance (homeostasis) by osteoblasts creating bone and osteoclasts destroying bone. Bisphosphonates inhibit the digestion of bone by encouraging osteoclasts to undergo apoptosis, or cell death, thereby slowing bone loss. The uses of bisphosphonates include the prevention and treatment of osteoporosis, Paget's disease of bone, bone metastasis (with or without hypercalcemia), multiple myeloma, primary hyperparathyroidism, osteogenesis imperfecta, fibrous dysplasia, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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