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| [[Superconductivity]] is the phenomenon of certain materials exhibiting zero [[electrical resistance]] and the expulsion of [[magnetic fields]] below a characteristic [[temperature]]. The '''history of superconductivity''' began with Dutch [[physicist]] [[Heike Kamerlingh Onnes]]'s discovery of superconductivity in [[mercury (element)|mercury]] in 1911. Since then, many other superconducting materials have been discovered and the theory of superconductivity has been developed. These subjects remain active areas of study in the field of [[condensed matter physics]].
| | Based on the research believe that cellulite begins when accumulating inflated (swollen) fat cells. Getting the proper types of training can dramatically improve a cellulite condition. Cellulite is actually a fancy name for collections of fat that push against the connective tissue beneath a person's skin, which causes the surface of the skin to dimple or pucker and look lumpy. With no results to show for the money wasted and time spent. Diet pills, sleeping pills and diuretics can all lead to cellulite; oral contraceptives, which increase the body's oestrogen, cause fat cells to enlarge, leading to water retention. <br><br>Whatever the cause of cellulite, it's important to know that there aren't any miracle products, treatments, or medicines that can make it go away. The excess will be stored by our bodies for later use. For this reason liposuction is not considered as medically necessary. However, if you are tight on the budget, a committed personality change is helpful. Yes, regular work out can help diminish the cellulite ' to some degree. <br><br>Lack of exercise, bad dietary habits, and poor circulation are equally to be blamed for this undesirable condition. It is in definite areas and begins on the inside surface of the thighs and the knees. Most of the sexual problems can easily preventable with homeopathic medicines and with self take care about vagina. The bottom line, however, is that if you really want to get rid of that dimpled fat, you will have to reduce your weight and do some cellulite exercises. Normal water is beneficial because it improves metabolic rate and it's also good for the epidermis. <br><br>Begin by standing straight, while your legs are stretch out to about a hip-width apart from each other. It is really just also easy to jump into the motor vehicle to go to city when it would probably only consider twenty minutes to walk there. With this perfectly normal condition, the fat is stored in pockets, creating those areas on the body that look like cottage cheese. The excess fat will then begin to push against your tissues, and muscles. Webmaster Marilyn Nelson who is the author of all-natural-skin-care provides with facts and advice of how to understand treatment of cellulites. <br><br>This is particularly good for areas that are hard to be exercised, like the inner areas of the thighs and the upper arms. Still, the unwanted cottage cheese or orange peel syndrome persists. They cannot depend on long time cellulite treatment. ” The part of the fruit that is specifically eyed due to its multi-faceted medicinal property is the stem. It has been suggested that the collagen in fibrous connective tissue (which tethers the skin to the underlying tissue) may be a major factor in why some ladies suffer while others don't.<br><br>If you loved this article therefore you would like to obtain more info concerning laser cellulite treatment ([http://www.samfinds.info/sitemap/ samfinds.info]) kindly visit our page. |
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| ==Exploring ultra-cold phenomena (to 1908)==
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| [[James Dewar]] initiated research into electrical resistance at low temperatures. [[Zygmunt Florenty Wroblewski]] conducted research into electrical properties at low temperatures, though his research ended early due to his accidental death. Around 1864, [[Karol Olszewski]] and Wroblewski predicted the electrical phenomena of dropping resistance levels at ultra-cold temperatures. Olszewski and Wroblewski documented evidence of this in the 1880s.
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| Dewar and [[John Ambrose Fleming]] predicted that at [[absolute zero]], pure metals would become perfect electromagnetic conductors (though, later, Dewar altered his opinion on the disappearance of resistance, believing that there would always be some resistance). [[Walther Nernst|Walther Hermann Nernst]] developed the [[third law of thermodynamics]] and stated that absolute zero was unattainable. [[Carl von Linde]] and [[William Hampson]], both commercial researchers, nearly at the same time filed for patents on the [[Joule-Thomson effect]] for the [[liquefaction of gases]]. Linde's patent was the climax of 20 years of systematic investigation of established facts, using a regenerative counterflow method. Hampson's designs was also of a regenerative method. The combined process became known as the [[Hampson-Linde cycle|Hampson-Linde liquefaction process]].
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| Onnes purchased a Linde machine for his research. On March 21, 1900, [[Nikola Tesla]] was granted a US patent for the means for increasing the intensity of electrical [[oscillation]]s by lowering the temperature, which was caused by lowered resistance, a phenomenon previously observed by Olszewski and Wroblewski. Within this patent it describes the increased intensity and duration of electric oscillations of a [[Cryogenics|low temperature]] [[resonator|resonating]] circuit. It is believed that Tesla had intended that Linde's machine would be used to attain the cooling agents.
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| A milestone was achieved on July 10, 1908 when [[Heike Kamerlingh Onnes]] at [[Leiden University]] in the Netherlands produced, for the first time, [[liquid helium|liquified helium]], which has a boiling point of 4.2 [[kelvin]] at atmospheric pressure.
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| ==Sudden and fundamental disappearance==
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| [[Heike Kamerlingh Onnes]] and Jacob Clay reinvestigated Dewars's earlier experiments on the reduction of resistance at low temperatures. Onnes began the investigations with [[platinum]] and [[gold]], replacing these later with [[mercury (element)|mercury]] (a more readily refinable material). Onnes's research into the resistivity of solid mercury at cryogenic temperatures was accomplished by using [[liquid helium]] as a refrigerant. On April 8, 1911, 16:00 hours Onnes noted "Kwik nagenoeg nul", which translates as "[Resistance of] mercury almost zero."<ref>[http://ilorentz.org/history/cold/DelftKes_HKO_PT.pdf The Discovery of Superconductivity]</ref> At the temperature of 4.19 K, he observed that the resistivity abruptly disappeared (the measuring device Onnes was using did not indicate any resistance). Onnes disclosed his research in 1911, in a paper titled "''On the Sudden Rate at Which the Resistance of Mercury Disappears.''" Onnes stated in that paper that the "specific resistance" became thousands of times less in amount relative to the best conductor at ordinary temperature. Onnes later reversed the process and found that at 4.2 K, the resistance returned to the material. The next year, Onnes published more articles about the phenomenon. Initially, Onnes called the phenomenon "''supraconductivity''" (1913) and, only later, adopted the term "''superconductivity.''" For his research, he was awarded the [[Nobel Prize in Physics]] in 1913.
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| Onnes conducted an experiment, in 1912, on the usability of superconductivity. Onnes introduced an electrical current into a superconductive ring and removed the battery that generated it. Upon measuring the electrical current, Onnes found that its intensity did not diminish with the time.<ref>{{cite book |author=V. L. Ginzburg, V.L. Ginzburg, E.A. Andryushin |title=Superconductivity |url=http://books.google.com/?id=4NtsKkwEQ4sC&q=Onnes+ring+switch#v=onepage&q=Onnes%20ring%20switch |publisher=World Scientific |isbn=978-981-238-913-8 |year=2004 }}</ref> The current persisted due to the superconductive state of the conductive medium. In subsequent decades, superconductivity was found in several other materials. In 1913, [[lead]] was found to superconduct at 7 K, and in 1941 [[niobium nitride]] was found to superconduct at 16 K.
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| ==Enigmas and solutions (1933–)==
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| The next important step in understanding superconductivity occurred in 1933, when [[Walter Meissner|Meissner]] and [[Robert Ochsenfeld|Ochsenfeld]] discovered that superconductors expelled applied magnetic fields, a phenomenon that has come to be known as the [[Meissner effect]]. In 1935, [[Fritz London|F.]] and [[Heinz London|H. London]] showed that the Meissner effect was a consequence of the minimization of the electromagnetic [[Thermodynamic free energy|free energy]] carried by superconducting current. In 1950, the phenomenological [[Ginzburg-Landau theory]] of superconductivity was devised by [[Lev Davidovich Landau|Landau]] and [[Vitalij Lazarevics Ginzburg|Ginzburg]].
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| The Ginzburg-Landau theory, which combined Landau's theory of second-order [[phase transition]]s with a [[Schrödinger equation|Schrödinger]]-like wave equation, had great success in explaining the macroscopic properties of superconductors. In particular, [[Alexei Alexeevich Abrikosov|Abrikosov]] showed that Ginzburg-Landau theory predicts the division of superconductors into the two categories now referred to as Type I and Type II. Abrikosov and Ginzburg were awarded the 2003 [[Nobel Prize in Physics]] for their work (Landau having died in 1968). Also in 1950, Maxwell and Reynolds ''et al.'' found that the critical temperature of a superconductor depends on the [[isotope|isotopic mass]] of the constituent [[chemical element|element]]. This important discovery pointed to the electron-phonon interaction as the microscopic mechanism responsible for superconductivity.
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| ===BCS Theory===
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| The complete microscopic theory of superconductivity was finally proposed in 1957 by [[John Bardeen|Bardeen]], [[Leon Neil Cooper|Cooper]], and [[John Robert Schrieffer|Schrieffer]]. This [[BCS theory]] explained the superconducting current as a superfluid of [[Cooper pair]]s, pairs of electrons interacting through the exchange of [[phonons]]. For this work, the authors were awarded the [[Nobel Prize in Physics]] in 1972. The BCS theory was set on a firmer footing in 1958, when [[Nikolay Bogolyubov|Bogoliubov]] showed that the BCS wavefunction, which had originally been derived from a variational argument, could be obtained using a canonical transformation of the electronic [[Hamiltonian (quantum mechanics)|Hamiltonian]]. In 1959, [[Lev Gor'kov]] showed that the BCS theory reduced to the Ginzburg-Landau theory close to the critical temperature. Gor'kov was the first to derive the superconducting phase evolution equation <math>2eV=\hbar\frac{\partial \phi}{\partial t}</math>.
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| ===Little-Parks effect===
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| The '''Little-Parks effect''' was discovered in 1962 in experiments with empty and thin-walled [[superconducting]] [[cylinder (geometry)|cylinder]]s subjected to a parallel [[magnetic field]]. The [[electrical resistance]] of such cylinders shows a periodic [[oscillation]] with the magnetic flux through the cylinder, the period being ''[[Planck constant|h]]''/2''[[elementary charge|e]]'' = 2.07×10<sup>−15</sup> V·s. The explanation provided by Little and Parks is that the resistance oscillation reflects a more fundamental phenomenon, i.e. periodic oscillation of the superconducting critical temperature (''T''<sub>c</sub>). This is the temperature at which the sample becomes superconducting. The Little-Parks effect is a result of collective quantum behavior of superconducting electrons. It reflects the general fact that it is the [[fluxoid]] rather than the flux which is quantized in superconductors. The Little-Parks effect demonstrates that the [[vector potential]] couples to an observable physical quantity, namely the superconducting critical temperature.
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| ==Commercial activity==
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| {{main|Technological applications of superconductivity}}
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| In 1962, the first commercial superconducting wire, a [[niobium-titanium]] alloy, was developed by researchers at [[Westinghouse Electric Corporation|Westinghouse]].
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| In the same year, [[Brian David Josephson|Josephson]] made the important theoretical prediction that a supercurrent can flow between two pieces of superconductor separated by a thin layer of insulator. This phenomenon, now called the [[Josephson effect]], is exploited by superconducting devices such as [[SQUID]]s. It is used in the most accurate available measurements of the [[magnetic flux quantum]] ''h''/2''e'', and thus (coupled with the [[quantum Hall effect|quantum Hall resistivity]]) for [[Planck's constant]] ''h''. Josephson was awarded the [[Nobel Prize in Physics]] for this work in 1973.
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| In 1973 {{chem|Nb|3|Ge}} found to have ''T''<sub>c</sub> of 23 K which remained the highest ambient-pressure ''T''<sub>c</sub> until the discovery of the cuprate high temperature superconductors in 1986 (see below).
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| ==High temperature superconductors==
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| {{main|High temperature superconductors}}
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| [[File:Sc_history.gif|thumb|Superconductor timeline]]
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| In 1986, [[Johannes Georg Bednorz|Bednorz]] and [[Karl Alexander Müller|Mueller]] discovered superconductivity in a [[lanthanum]]-based cuprate [[perovskite]] material, which had a transition temperature of 35 K (Nobel Prize in Physics, 1987) and was the first of the [[high temperature superconductor]]s. It was shortly found (by [[Ching-Wu Chu]]) that replacing the lanthanum with [[yttrium]], i.e. making [[YBCO]], raised the critical temperature to 92 K, which was important because [[liquid nitrogen]] could then be used as a refrigerant (at atmospheric pressure, the boiling point of nitrogen is 77 K.) This is important commercially because liquid nitrogen can be produced cheaply on-site with no raw materials, and is not prone to some of the problems (solid air plugs, etc.) of helium in piping. Many other cuprate superconductors have since been discovered, and the theory of superconductivity in these materials is one of the major outstanding challenges of theoretical [[condensed matter physics]].
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| In March 2001 superconductivity of [[Magnesium diboride]] ({{chem|Mg||B|2}}) was found with T<sub>c</sub> of 39 K.
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| In 2008 the [[oxypnictide]] or [[iron-based superconductor]]s were discovered which led to a flurry of work in the hope that studying them would provide a theory of the cuprate superconductors.
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| ==Historical publications==
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| '''Papers by H.K. Onnes'''
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| * "The resistance of pure mercury at helium temperatures". ''Comm. Leiden''. April 28, 1911.
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| * "The disappearance of the resistivity of mercury". ''Comm. Leiden''. May 27, 1911.
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| * "On the sudden change in the rate at which the resistance of mercury disappears". ''Comm. Leiden''. November 25, 1911.
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| * "The imitation of an ampere molecular current or a permanent magnet by means of a supraconductor". ''Comm. Leiden''. 1914.
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| '''BCS theory'''
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| * J. Bardeen, L.N. Cooper and J.R. Schrieffer, "Theory of superconductivity," ''Phys. Rev.'' '''108''', 1175 (1957), {{doi|10.1103/PhysRev.108.1175}}
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| '''Other key papers'''
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| * W. Meissner and R. Ochsenfeld, ''Naturwiss.'' '''21''', 787 (1933), {{doi|10.1007/BF01504252}}
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| * F. London and H. London, "The electromagnetic equations of the supraconductor," ''Proc. Roy. Soc. (London)'' '''A149''', 71 (1935), [http://www.jstor.org/stable/96265 ISSN 0080-4630].
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| * V.L. Ginzburg and L.D. Landau, ''Zh. Eksp. Teor. Fiz.'' '''20''', 1064 (1950)
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| * E. Maxwell, "Isotope effect in the superconductivity of mercury" ''Phys. Rev.'' '''78''', 477 (1950), {{doi|10.1103/PhysRev.78.477}}
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| * C.A. Reynolds ''et al.'', "Superconductivity of isotopes of mercury," ''Phys. Rev.'' '''78''', 487 (1950), {{doi|10.1103/PhysRev.78.487}}
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| * A.A. Abrikosov, "On the magnetic properties of superconductors of the second group," ''Soviet Physics JETP'' '''5''', 1174 (1957)
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| * W.A. Little and R. D. Parks, "Observation of quantum periodicity in the transition temperature of a superconducting cylinder," ''Phys. Rev. Lett.'' '''9''', 9 (1962) {{doi|10.1103/PhysRevLett.9.9}}
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| * B.D. Josephson, "Possible new effects in superconductive tunnelling," ''Physics Letters'' '''1''', 251 (1962), {{doi|10.1016/0031-9163(62)91369-0}}
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| '''Patents'''
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| * Tesla, Nikola, {{US patent|685012}} "''Means for Increasing the Intensity of Electrical Oscillations''", March 21, 1900.
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| == See also ==
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| * [[Superconductivity]]
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| * [[Macroscopic quantum phenomena]]
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| * [[Timeline of low-temperature technology]]
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| * [[Technological applications of superconductivity]]
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| * [[High-temperature superconductivity]]
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| ==External links and references==
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| {{Reflist}}
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| * Heike Kamerlingh Onnes, "''[http://nobelprize.org/physics/laureates/1913/onnes-lecture.pdf Investigations into the properties of substances at low temperatures, which have led, amongst other things, to the preparation of liquid helium]''," Nobel Lecture, December 11, 1913
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| * M. Tinkham, ''Introduction to Superconductivity'', 2nd Ed., McGraw-Hill, NY, 1996, ISBN 0-486-43503-2
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| * T. Shachtman, ''Absolute Zero and the Conquest of Cold'', Houghton Mifflin Co., 1999, ISBN 0-395-93888-0
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| * J. Matricon, G. Waysand and C. Glashausser, ''The Cold Wars: A History of Superconductivity'', Rutgers University Press, 2003, ISBN 0-8135-3295-7
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| * J. Schmalian, ''[http://arxiv.org/ftp/arxiv/papers/1008/1008.0447.pdf Failed theories of superconductivity]''
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| {{DEFAULTSORT:History Of Superconductivity}}
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| [[Category:Condensed matter physics]]
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| [[Category:Superconductivity]]
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| [[Category:History of physics|Superconductivity]]
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Based on the research believe that cellulite begins when accumulating inflated (swollen) fat cells. Getting the proper types of training can dramatically improve a cellulite condition. Cellulite is actually a fancy name for collections of fat that push against the connective tissue beneath a person's skin, which causes the surface of the skin to dimple or pucker and look lumpy. With no results to show for the money wasted and time spent. Diet pills, sleeping pills and diuretics can all lead to cellulite; oral contraceptives, which increase the body's oestrogen, cause fat cells to enlarge, leading to water retention.
Whatever the cause of cellulite, it's important to know that there aren't any miracle products, treatments, or medicines that can make it go away. The excess will be stored by our bodies for later use. For this reason liposuction is not considered as medically necessary. However, if you are tight on the budget, a committed personality change is helpful. Yes, regular work out can help diminish the cellulite ' to some degree.
Lack of exercise, bad dietary habits, and poor circulation are equally to be blamed for this undesirable condition. It is in definite areas and begins on the inside surface of the thighs and the knees. Most of the sexual problems can easily preventable with homeopathic medicines and with self take care about vagina. The bottom line, however, is that if you really want to get rid of that dimpled fat, you will have to reduce your weight and do some cellulite exercises. Normal water is beneficial because it improves metabolic rate and it's also good for the epidermis.
Begin by standing straight, while your legs are stretch out to about a hip-width apart from each other. It is really just also easy to jump into the motor vehicle to go to city when it would probably only consider twenty minutes to walk there. With this perfectly normal condition, the fat is stored in pockets, creating those areas on the body that look like cottage cheese. The excess fat will then begin to push against your tissues, and muscles. Webmaster Marilyn Nelson who is the author of all-natural-skin-care provides with facts and advice of how to understand treatment of cellulites.
This is particularly good for areas that are hard to be exercised, like the inner areas of the thighs and the upper arms. Still, the unwanted cottage cheese or orange peel syndrome persists. They cannot depend on long time cellulite treatment. ” The part of the fruit that is specifically eyed due to its multi-faceted medicinal property is the stem. It has been suggested that the collagen in fibrous connective tissue (which tethers the skin to the underlying tissue) may be a major factor in why some ladies suffer while others don't.
If you loved this article therefore you would like to obtain more info concerning laser cellulite treatment (samfinds.info) kindly visit our page.